7 Symptoms of a Bad Transmission Control Module (and Replacement Cost)

Updated

The transmission control module (TCM) is a vital component of any vehicle with an automatic transmission system. Rather than relying on hydraulic or mechanical control over a transmission system, newer vehicles use a transmission control module instead.

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A car’s TCM will likely never need replacing, but if you have a bad transmission control module, immediate replacement (or repair) will be necessary. This module is basically a computer which communicates information to other computer systems within the vehicle.

The purpose of the transmission control module is to help the automatic transmission choose the best gear to be in at any given time. That way, the driving performance and fuel economy will be at the optimal level.

See Also: PCM vs ECU vs ECM vs TCM (What’s the Difference?)

Signs of a Bad Transmission Control Module

The transmission control module can often be found below the cover at the back of the transmission case. It should be just below the engine control module’s position. Sometimes it’s found under the center console in the interior or even under the hood near the battery or inner fender panel.

If you ever have a problem with your transmission control module, you’ll need to have it inspected right away. A bad TCM will spell trouble for your vehicle and your ability to drive it. Fortunately, there are a few basic symptoms that you’ll most likely notice before this happens.

#1 – Check Engine Light

bad-tcm-symptoms

If the Check Engine warning light illuminates on your dashboard, it could mean several things. But if you notice any problems with your shifting in addition to the Check Engine light being on, then it is most likely a problem with your transmission control module or some other component of your transmission system.

In any event, get your vehicle checked out immediately by a mechanic or use your own scan tool to check for any Diagnostic Trouble Codes (DTC). If code P0700 shows up, you likely have a problem with your transmission control module.

#2 – Unpredictable Shifting

automatic transmission shifting

Since an automatic transmission system relies on the transmission control module to do the shifting, a bad transmission module will cause incorrect or unintended shifting. This can prove to be anything from an annoyance to causing a serious accident.

For instance, if your car shifts to neutral or any other gear that it normally wouldn’t shift into without warning, then your control module will likely need to be replaced. Otherwise, it will be very dangerous to continue driving.

Unless you have a manual override option in your vehicle (example: paddle shifters), you will need to get your car towed to a repair shop and have the module replaced.

#3 – Problems Shifting Into Higher Gears

high RPM tachometer

As you gradually increase speed, your transmission should correctly shift into higher gears at the correct time. When this doesn’t happen, you’ll notice that your engine’s RPM simply keeps increasing instead of slightly dropping an upshift occurs.

Because each gear has a maximum speed it can go to, you may never reach your intended speed if the faulty TCM refuses to shift to a higher gear.

#4 – Problems Downshifting

can't downshift

This is similar as above but in reverse order. Maybe you need to pass a slow moving vehicle and your transmission fails to shift into a lower gear when you mash the gas pedal to help you accelerate.

Or you’re cruising down the freeway and take an off-ramp, your transmission should gradually be going into lower gears as your speed decreases. At a stop, an automatic transmission should be in first gear so it’s ready to go when you need to start moving again.

If your transmission control module is bad, you may still be in a high gear as you’re coming to a stop. When it’s time to start moving again, you’re in a too high a gear for proper acceleration which may even prevent you from moving at all.

#5 – Stuck in the Same Gear

tire noise

This usually presents itself as being either stuck in neutral or first gear. The transmission simply will not shift and you either won’t be going anywhere (stuck in neutral) or you’ll be limited by the maximum speed of first gear.

#6 – Delayed Shifting

reasons and causes of car not accelerating

The speed of your vehicle relies on cycling to various gears at the appropriate timing. If you have a bad transmission control module, then it will cycle to next gear too slowly.

This will impact your acceleration, causing you to lose speed rather than picking up speed. When you approach a hill, the shifting performance will be even worse.

Worst case is when you’re attempting to pass a slower vehicle on a 2-lane road and your vehicle refuses to downshift immediately so you have more torque available to make a quick pass.

#7 – Poor Fuel Economy

poor gas mileage

Problems with your transmission system usually result in bad fuel economy. An automatic transmission is designed for optimal gear selection and timing to provide you with the best possible fuel economy.

If you have a transmission control module that’s bad and affects this timing, then your engine will end up working harder than usual. This means it will consume more fuel than usual, causing you to spend more money at the gas pump.

Replacement Cost

For replacement parts, we recommend: PartsGeek.com

transmission control module replacement cost

The replacement cost of a transmission control module will be anywhere from $500 to $900. You can expect the parts costs to be around $450 to $700 while the labor costs will be around $50 to $200.

Of course, you can order a new TCM online and ask a mechanic what their hourly labor rates are. However, most of the cost for this replacement job goes toward the parts cost itself and it can vary greatly by car manufacturer. You can expect taxes and fees to be added to the total cost as well.

Repair Cost

Another option is to repair your TCM. The transmission control module repair cost will in almost all cases be lower than replacing with a new module. On average, expect to pay around $300 to repair your transmission control module.

While most TCM repair businesses will offer a warranty of some sort, it does pose a bit more risk if the repair is not done right.

Also, you may need to ship your bad TCM to a non-local location so if you can’t afford not having your vehicle for a few days, replacement would be the fastest method.

 

Comments

    • Just like any other computer, failure of the TCM is often due to an electrical issue (such as a voltage overload), water (corrosion builds up and eventually causes a short circuit), or damage due to too much vibration or stress.

      Reply
      • I have a Ford F-350 super duty diesel truck. The truck starts up fine. But It sometimes doesn’t do anything no crank no nothing. Then after waiting two days it starts up just fine. The scan code U0101 came up. Could it be a faulty wire or corroded wire or and all out faulty TCM.

        Reply
  1. Will a bad transmission control module cause irregular motor revs as well as confusing shifting,

    Let me explain a bit further

    i own a 2003 Dodge Durango 4.7 AWD with 4×4
    last week i was driving down the highway in town, traffic started to slow and the durango went from just coasting at about 70 km/h with about 1000 rpm and did a really hard and sudden down shift into low range …given the speed i was able to maintain at 5000 rpm i knew it was in 2

    i got off the highway let the truck cool down which did not take long since it was minus 35 c

    i started the truck and then the rpm started waving between 500 rpm and 1500 rpm just randomly, i figured it must be the Throttle Position Sensor, I started to head back to my house to park and about half way there when truck hit normal operating temp it started randomly shifting in and out of low range sometimes putting itself into too high of a gear and would stall out, after getting it home i realized it needed a new alternator and battery, so out i went and replaced those along with the Throttle positioning sensor in the freezing cold, got it running and at first it was doing the same thing with the RPM also the voltage meter on the dash was leaning to the right just a bit off center but according to the voltage tester i was perfect, so i scanned it with OBD2 and it threw a TPS and TCM code, so i took it for a drive knowing the TPS was new and needed to do its thing, had my buddie run a live scan with his machine while we were driving, and both codes cleared themselves, Yesterday in minus 30 c weather it started doing the same thing again only the RPM dont fluctuate as much but transmission goes from like 4th gear for instance and drops to low range and will shift if i hammer it , when it starts the RPM is really high at idle ….1800 to 2100 and will rev on its own in that range until i give it a shot of gas then it levels down to about 800-1100 and once again revs in that range on its own, when the operating temp is cold it will shift like its supposed to , once operating temp is achieved it begins selecting random gears, usually Low range 1 and Low Range 2, if i punch it hard it will shift but not until rpm’s get above 6000 which is insane,

    Reply
    • Get rid of the thing and save yourself a boat load of money and future headaches. I loved my Durangos. Had three of them, 03, 04, and 05, unfortunately along with tranny issues the 4.7’s were just a s*** engine compared to the 5.3’s and 5.7’s. Not sure where they went wrong with the 4.7’s but trust me and speaking from experience when something major starts to malfunction its good night time for the D.

      Reply
  2. Kindly I need help please. My vehicle is unable to start, is just cranking. We tried to check the all electrical components and they are working. What could be the problem?

    Reply
    • Unfortunately it could be other things. Bad fuel pump, clogged fuel filter, fuse, and bad crank position sensor come to mind.

      Reply
      • Hey i have an AUDI A4 B7 2.0t multitronic. My car select all the gear but when you select D and drive it only drive in 1st gear it does not conrinue shifting upwards. And when im on a downhill and not accelerate it changes itself but once i accelerate it goes back to 1st gear. Can it be a TCU issues…. please help

        Reply
    • What does it mean when you’re at a stop sign and the rpms fluctuate and it acts like it want to go what can that be? Can anyone help me?

      Reply
      • It could mean there is a problem with the air fuel ratio with the throttle plate closed. This could be caused by a dirty mass airflow (MAF) sensor, carbon buildup, a bad idle air control (IAC), or a number of other factors. Scan for codes, as these may give you a clue. If there are no codes, check the spark plugs and look for vacuum leaks.

        Reply
  3. 2001 pt cruiser in limp mode diagnosed pcm replaced with new one also transmission solenoid with input and output sensors transmission oil with filter still same need help

    Reply
  4. Good morning, my 2010 Chevy Tahoe had been having issues getting into first gear with very slow acceleration but RPM into the 2000 range. At first it would take a hard here then after the first gear it’s fine. I was told that was being caused by the motor mount needing to be replaced. Fast forward months later I haven’t fixed the motor mount but now I’m getting the transmission control module or solenoid error. Is the transmission module or maybe the mount replacement

    Reply
    • Not sure what a bad motor mount would have to do with your first gear issues. I can’t tell if you’ve scanned the ECU for trouble codes but if it was the transmission control module, it would show up there.

      Reply
  5. I have a 2013 dodge dart areo 1.4l double clutch transmission. The TCMs were recalled but I had no idea of this recall until my transmission started grinding and clanking. Now my transmission is out. Is the tcm to blame for this. And if so. How am to go about getting the dodge dealership to pay for a new transmission in my car?

    Reply
  6. I have a 2012 Chevy Cruze. The engine was slipping between gears 2-3 and 3-4. The tachometer would flare, and the engine would race before it shifted into a higher gear. It also had a rough downshift that felt like a jerk or pop of the clutch. It worked best at cold temperatures but had the most problems when it was hotter outside. I took it to a transmission specialist, and they determined that it was the “transmission control module”. They didn’t have to take out the whole transmission to get to it, but it was quite a bit a work and ran upwards of around $1,500 to fix. In the end it was worth it for us, because we weren’t in a position to trade up.

    Reply
  7. We have a 2012 Dodge Ram 2500 Diesel Cummins 6.7. The truck is stuck in 4th gear it will not shift in a lower or higher gear. It all started December 4th of 2018. Did a few things in town, when to my mother in laws, cooled down the truck turned it off, went inside for about 25 to 30 minutes, went to start the truck, put it in gear to leave and it was stuck in forth gear. We just brought new batteries on April 24th thinking that was the problem. Please help we need our truck for work.

    Reply
    • Sounds like your shift solenoid is bad. Having the truck scanned for codes should confirm. I believe P0750 is the code in your case.

      Reply
  8. Hi,
    l have KIA RIO 2012. The TCM is faulty. The tranmission gear stuck at 3. I wanted to replace it for a new one. Where l can l get it.
    Thank You.

    Reply
  9. I have a 2013 Ford Kuga 2.0l diesel AWD. I had problems with my transmission and have been diagnosed by Ford with scanned DTC’s PO700, PO766, & PO771 present.
    They have said that it requires replacement valve body/TCM but quoted me AUS $13,364.38 to fix it – + labour of $1158.16.
    Is this realistic?

    Reply
    • They don’t call dealerships “stealerships” for no reason. I’d definitely get another quote from an independent shop. It still won’t be cheap but the price you mentioned is just ridiculous.

      Reply
  10. Hi, my 2007 nissan altima starts up fine but won’t move when placed in any gear. I wish to know if my tcm is bad? Thanks

    Reply
    • I have a 2010 Chevy Silverado 1500 flex fuel with a 4.8liter engine. It drives fine in first and second but the when it is supposed to shift to third the rpms go up but nothing. Tried switching the 1-2 and 3-4 sensor in the transmission but still the same result no third or fourth. The trans guy thought it might be the TCM but it’s not throwing a TCM code. On another note, I cleaned the throttle body and now my starting rpms are 2000+. I’ve tried relearning procedures but nothing is working. I’ve order a new throttle body and sensor hopefully that fixes that issue.

      Reply
  11. Hello, My 2003 Nissan Frontier V6 engine shift okay at plain surfaces but the engine seems like pulling very heavy load at high hills and really slow. Brakes, egr valve check out okay. What might cause heavy load aside gravity pull when it climing?

    Reply
  12. I have got a CX7 2007 . Engine light came on , tracking light on . It starts sometimes sometimes not..I scanned it up and came up like lost communication..A bad TCM will make not starting the car?

    Reply
    • It’s possible. If the TCM is bad, it might send a faulty signal to the PCM saying that the transmission is in gear when it’s actually in Park. This would prevent the car from starting.

      Reply
  13. Nice tips up there. Please help me on this… ‘After replacing my 2003 MDX tranny, it shifts into neutral before shifting roughly into the next gear. It downshifts well when I slow down but shifts up roughly. If I try taking off speedily, once it wants to up shift it neutralizes first before it roughly hits in the next gear. Could this be a problem with the TCM(that’s if it has one)?

    Reply
    • Yes, the TCM could be the culprit. Unfortunately, MDX transmissions around that year are known to have a relatively high failure rate.

      Reply
      • Thanks for the reply. I replaced the first one that failed after purchasing the vehicle. I had to take it away from the mechanic who replaced the transmission since he couldn’t figure why it was shifting roughly. I forgot to mention that when in reverse, it delays 4-6 seconds before engaging. Any ideas if the 2003 transmission has the TCM? If so, please where can I locate it?

        Reply
  14. Hello, i need help, i parked my bmw E36, then now when i start and shift to drive mode is not moving, infact all the gears, no movement. What could be the problem

    Reply
  15. My transmission shop (very reputable) having difficulty finding transmission computer for my 06 PT Cruiser. One place in N Y sent one but it is defective. Are there any manufacturers of this computer?

    Reply
  16. I have a 2010 Subaru Forrester and recently had the transmission replaced with a working, used one (mine died on the road, due to a family member driving with an untreated leak).
    Now a week after the replacement of the transmission, the car is driving again but having sone of the symptoms above, which were similar to the symptoms immediately before the transmission dies in the first place. Now, however, the diagnostic says there’s a TCM fault.
    When the transmission died, could or have affected the TCM?
    Could the TCM have been having a fault and been the actual cause of the transmission issue (rather than the leak)?

    Basically what are the odds that the TCM would have a fault soon after the transmission died and was replaced?

    Reply
    • Do you remember what the exact TCM fault code was? It’s possibly a wiring issue from the TCM to the transmission. I doubt the original issue was the TCM but did you happen to scan for fault codes before replacing the transmission?

      Reply
        • It’s a communication issue with the transmission so it could also be wiring or a faulty sensor. Try unhooking the battery for a few minutes to allow the ECU to reset and see if the codes come back. A lot of these types of codes can be false positives.

  17. I have an 04 Dodge Ram with the check engine light on the trans will not shift into overdrive or down shift unless I do it manually. The codes showing are po700 and po760. Replaced the Shift solenoid pack cleared codes just to have the same codes come back on, so I changed the valve body cleared codes but they came right back. Any ideas I am running out of suggestions? TCM?

    Reply
  18. Hi I have nissan safari td42t 1995 auto transmission. 2 months back I bought it and within no time like after a week I got blown gasket because of unthinkable problem. So, I asked my mechanic to get it overhauled as the jeep was 2nd hand.

    At the time of purchase, during trial ride I had a feeling that there is some problem in gear shifting, I didn’t took it seriously and bought it. Well, after the overhauling the gear really showed me the stars, rightnow my jeep current position is that iam driving it manually like in two gears 1 n 2. If I set my jeep transmission to D she gets dead, huge loss in amount of pressure. Well the reverse is working too but again like without any amount of pressure the way it should be keeping in mind a six cylinder giant crawling like an ant.

    Would really appreciate if you guys can help me out finding that whether its TCM or transmission problem and how can I get it fixed.

    Reply
  19. 2009 Mercury Milan 2.3 L – Automatic with Mazda FNR5 transmission

    P0748 – Pressure Control Solenoid A with Orange Wrench Light. Car drives perfect in forward with hard shift into reverse.

    Checked fluid, removed pan, magnet was very clean, and replaced the PCA solenoid. Checked resistance of both the old and new solenoids and tested within specification.

    Purchased used TCM on ebay. Installed and the orange wrench light was off for about 1 minute of driving. Turned car off. Next day, orange light was off for about 10 minutes but turned back on. Car left at school. Car was driven in the afternoon and turned back on after about 5 minutes and has stayed on since.

    Removed and replaced with a new refurbished and tested valve body assembly. No change.

    Performed continuity and Ohm check with multimeter from TCM to connections on transmission. Also performed Ohm check on solenoids from the pin connections. No faults found.

    Reply
  20. I have a 2007 Dodge charger 3.5 Liter! Runs great till it warms up then you will hear this whining noise in Transmission you can stop and shut off and crank and go again don’t hear it no more,till it starts again.If you continue running it with whining noise the transmission will just go out just stop shut off and crank and go again. Ive been told Transmission needs rebuilding but I believe it’s just electrical not mechanical!

    Reply
  21. I have a 2005 jeep wrangler tj sport. Its throwing 4 codes for the transmission which are p0700, p1604, p1775 and p0613. I feel like the mechanic is trying to screw me on repairs. With these codes do I need to rebuild the transmission and replace the tcm like mechanic says or what needs to be done

    Reply
  22. I have a 2006 Chevrolet Equinox AWD. I had 3rd gear slipping for awhile. Then after I gave The car to my daughter one day transmission stopped Working completely, no reverse no drive, nothing!!!! When I turned car off for a few minutes and restarted it transmission started working again, but soon after stopped again.T/C light along with engine light went on. I erased engine light. I repeated what I did b4 and was able to drive 2 miles home. I purchased a used transmission control module, installed it and proceeded to drive car. Car drove great, shifted like it was supposed to for about 4 miles then again transmission started slipping again, until it wouldn’t move anymore. No drive, no reverse,nothing. I turned car off 1 minute later I started car and off i went 1 1/2 miles home. Does anyone know if this sounds like transmission control module problem? considering My original TCM was potentially bad, and the used one I bought although different symptoms similar results, no drive or reverse, but no engine or T/C light on 2nd TCM

    Reply
  23. I am owning Ford Focus 2L GDI trend powershift. It started to give me problem just before I took it for140000KM service plan. When it gets hot the car will stall if is in motion(on D) and it won’t show on the display whether is on D, R, N, S, & P. The engen will keep on running but the car won’t move. If that happened while it was on Park(P) the gear lever will get stuck until you switch it off. If it’s still hot it won’t show anything on the screen but as soon as it cools down, it will now show when ignition switched on. It will go as normal until gets hot again. Please advise dealership said TCM needs replacement. Should I go buy it or it might be something else?

    Reply
  24. I have a UD truck 440 automatic, it doesn’t want to shift the gears, u can travel for a distance without a problem, once it starts by releasing pressure continually it shows economy , no raves and the gears will not shift, wat might be a problem

    Reply
  25. I just replaced the transmission on my 2008 Jeep Grand Cherokee. It is not shifting properly. The RPM’s are really high befor the shift kicks in. I have been told I need to have the TCM reprogrammed. Is it possible and if so about how much does this cost ball park?

    Reply
    • I’d recommend calling a local repair shop or Chrystler/Dodge/Jeep dealership. Some TCMs don’t need reprogramming and they “learn” as you drive, some require a “reset”, and other require reprogramming. Often reprogramming can be done via a regular OBD2 scan tool.

      Reply
  26. Just had my transmission rebuilt on a 09 3500 chevy cutaway van only 55k miles. Charged me 3400$. Is that a fair price?
    Also told me to come back after driving 800 miles so he could reflash. Is that normal procedure? I thought he would have done this already. Any info would be appreciated thanks

    Reply
  27. I have a 2012 nissian altima the brake,abs,an traction lights will flash on an car goes from 60 to 5mph an has a jerk if released accelerator lights goes off press accelerator they come back on…any idea whats going on, has anyone else experienced this.

    Reply
  28. I took my 2012 Kia Sorento in to a transmission shop with code P0700, they switched a grounding wire, a pin, and later a sensor, the downshifting problem is still not fixed, now they said it’s a code reset that only a Kia dealership can perform, is this the same as the TCM, or something different.

    Reply
  29. Hi
    I have a mazda 3 2014
    I was driving and the engine light came up and the car got slower i took it to mechanic and they said it has TCM problem which is gonna cost alot of money to replace it . After checking it the next day everything seems normal no engine light on , does it mean i don’t have to replace the TCM

    Reply
    • When the issue first happened, the car may have switched into limp mode. You likely do have an issue with the TCM if that’s what the mechanic found after scanning for codes. Sometimes a code will temporarily clear itself but there’s a good chance it will occur again. Keep an eye on it.

      Reply
  30. Hi I have a Volvo S60 Auto D5 2004 model, the codes is tcm-0002 and tcm-0115 do I have to replace the solenoids or what could be the problem.pls help

    Reply
  31. I have Nissan xtrail 2.0 4wd from malaysia …. when i put it in D the engine engage like its in gear but the car wont accelarate…. i try to put in R or other gear is same… the engine engage like in gear but no accelaration… i try to pull out socket in tcm and its same.. the engine still engage like in gear but no accelaration…. if that mean i need a new tcm?

    Reply
  32. i have unusual problem,while driving 1997 ck1500 (new engine and trans from GM)
    as I am driving in any gear it jerks and at times jerks hard,all new parts on engine when i replaced it.( no codes,and scanner says all is well,4L60E trans)
    had it to a gm dealer and they dont know,i have had it other repair places,all come up with same ,cant figure it out.
    i pull a car trailer with a car in it to shows,and dont seem to jerk at all.
    i need help finding this problem,taking a long trip ,

    Reply
  33. Hi

    I have a Subaru Forester 2010 with a 2.5l engine and automatic transmission. It starts ok , engage gear without problem but hesitate when I ask for accelaration.

    From a dead start, at normal temperature, the engine does not seems to have the power to move the vehicule and it finaly does it by gradually accepting to accelerate. And to acheive that, I have to lightly play with the gaz pedal. Accelaration feels stronger as it gets closer to 3,000 rpm. Riding between 35 and 50 mph seems to be the ‘safe’ region. If I try to go faster, the transmission downshifts, sometimes 2 gears, but the vehicule won’t go any faster, just rev to the limiter! Like a slipping clutch on a manual transmission.

    Lately, I had 2 bad situations :
    – once, the engine sudenly slowed down from 30 mph to around 3 mph for a thousand feet before regaining life and
    – at another time, it simply shut down; I had to coast to the side of the street, put the transmission on Park and restart the engine to continue my trip (I was almost at home).

    When the vehicule has been run for let say 10-15 min, it begins to emit a harsh low sound, telling that it’s not happy at all to ride.

    The code say TCM but I have a hard time believing that this module can produce ALL of those symptoms. On a Forester, the dealer is asking 1650$ for the module and say that it might not be the only problem!

    I first thaught that it was a faulty accelarator sensor but I have no way to diagnose this other than the symptoms.

    What would be your take on that?

    Thanks

    Reply
    • It definitely sounds like a transmission issue. Hard to say if it’s just the TCM at fault or if the TCM is indicating there is a different problem, without knowing the code.

      Reply
  34. I have a 2015 GMC Yukon XL.

    When I went to get in to leave from somewhere the other day, I backed up, put it in drive and nothing. Transmission completely stopped working. I only have reverse. Motor is strong, lots of power when reversing. No symptoms or signs before this happened, had drove it on a 4 hour trip a week prior without issue.

    Check engine light came on, I have codes: P0700, U0100,U0101 and U0073.

    No flakes in the fluid and I fired it up today and the check engine light is now off. I haven’t tried to put it in gear to drive though.

    Your response is greatly appreciated!

    Reply
    • How strange. It sounds like the modules are having a hard time talking to each other. Check the wiring harnesses near the ECU and TCU if you know where these are. Look for any obvious signs of holes or breaks in the wiring. Sometimes rodents will actually chew through wires.

      If you don’t see anything, see if there is a technical service bulletin (TSB) or recall out for an issue with the ECU or TCU on your vehicle. These modules may also be called ECM, TCU, TCM, or PCM (different manufacturers use slightly different acronyms for the engine and transmission computers).

      Consider bringing your vehicle into the dealership if it’s still under warranty.

      Reply
  35. Could a bad TCM system cause my 2003 Dodge Ram 1500 to shut off while stopped at red lights and stop signs? It usually starts up fine and drives good for about 5-10 minutes, but after driving for a while and stopping my truck starts to shut off.

    Reply
    • I would expect a check engine light if the TCM failed, not an engine stall. A failed or failing TCM may cause the vehicle to run in limp mode. This often will mean the vehicle has reduced power and will be stuck in one or two gears.

      Reply
  36. 2002 excursion. Tranny stop functions overnight. Was scanned a couple weeks ago and clutch sensor popped up. This AM putting it in gear and nothing happens until high rev

    Reply
    • I have a 2009 Chevy Silverado 4.8L 4×4 that popped up service stabilitrak while I was sitting in a fast food restaurant drive thru. It is in limp mode now slowly accelerating from take of & will not shift passed 2nd or 3rd. OBD2 scanner says lost communication with TCM. Also my digital transmission temp guage – – – instead of telling me its temp. My reverse will not come on in reverse but will when its in park & I turn truck off. My door lock periodically lock & unlock on their own. I changed my throttle body about 6-12 months ago & haven’t had any problems or throttle codes pop up since. PLZ HELP!

      Reply
      • Sounds like you have an electrical issue that’s affecting a few things. Check all your ground straps to make sure they are clean and tight, with no corrosion. Check that the battery terminals are also tight and free of corrosion.

        Reply
  37. Battery is good & I even added a ground but still no luck. I also changed the brake pedal switch thinking that might be it because when I press the brake & let of it there is a loud clicking noise but still no luck

    Reply
  38. All of these issues happen in my 2004 Mazda 6i 2.4L . We connected an OBD2 reader and it didnt throw any codes. Is this normal for the TCM?

    Reply
    • Sometimes transmission issues won’t necessarily throw a code for the OBD2 reader.

      OBD2 is only designed to detect certain kinds of failures, such as an interrupted communication between the TCM and ECM, failure of emissions components, and misfires. If it is a mechanical issue with the transmission, you may experience some of these symptoms with no OBD2 code.

      Reply
  39. Kindly help
    I have Ford Fiesta currently having transmission malfunction.
    Run DTC and found these codes:
    P0700 – Transmission Control System Malfunction
    P287A – Clutch “B” Stuck Engaged
    P2872 – Clutch “A” Stuck Engaged
    P2701 – Transm friction element B, apply time – range/performance problem
    P0882 – TCM – power input signal low
    P07A5 – Transm friction element B, stuck on
    P07A4 – Transm friction element B, performance or stuck off
    P0702 – Transm Control System electrical
    P06B8 – internal control module, non-volatile memory – error

    Reply
    • Wow, that’s a lot of codes. The good news is when you see so many codes, you often have an issue that throws many codes at once.

      Start with the transmission control module. Visually inspect the TCM for any issues with the wiring. I would also give the ECU a look since the two systems need to be able to talk to each other.

      Once the visual inspection checks out, you can try testing with a multimeter to make sure the systems are able to communicate as expected. To do this, you will need a factory service manual with a wiring diagram.

      If you’re not comfortable with this level of electrical troubleshooting (which I totally understand), it would be best to take your vehicle to a mechanic and pay their diagnostic fee. They should figure out the root cause of the problem and give you an estimate for the cost of the repair.

      That last code (P06B8 – internal control module, non-volatile memory – error) sounds to me like the TCM has gone bad. Non-volatile memory is permanent storage, like the hard drive in your computer. If the TCM has an issue with its permanent storage, its programming could become corrupted and cause the unit to malfunction.

      Reply
  40. I have a 2007 Chevy Cobalt. I’ve been having issues with the TCM for a year now. Every now and then, Power Steering appears on my DIC, and my car becomes harder to steer. We’ve replaced the Transmission Control Module and replaced the disintegrating wires so we thought the issue was fixed. A few weeks ago, I was driving and had this problem upon startup again. Once I got on the road and shifted into 3rd gear, something in the car kicked and suddenly my speedometer came back on and everything went back to normal as I was driving. So my question is: can a TCM come back online at random or is there something I’m missing?

    Reply
    • If there’s a bad ground or disintegrating wires, the system(s) which share that circuit may work intermittently, yes.

      However, I don’t think the TCM would be related to your power steering issue. Check a wiring diagram to be sure, but it seems like you have two separate issues going on.

      Reply

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