What’s an Engine Control Module (ECM)?
If your car had a brain, the ECM would be it.
The Engine Control Module (ECM), also known as the Engine Control Unit (ECU) or Powertrain Control Module (PCM), is one of the most critical components found in modern vehicles. This piece of equipment essentially acts as the main computer system for many of the vehicle’s engine performance and drivability systems. The various sensors in the engine relay information to the ECM and that information is used to calculate and tune engine spark and fuel for maximum efficiency and power. In laymen’s terms, if your car had a brain – this would be it.
Since the ECM is such a critical piece of equipment, when it begins to fail, the car may become undrivable altogether. When problems arise with the ECM, there are some key symptoms to alert you to the situation.
Signs of a Bad ECM
Check Engine Light Is Illuminated
A check engine light does not immediately indicate a problem with the ECM, however, it always indicates an issue with the engine. Sometimes, this light can be triggered when there are no issues present, but a simple test will determine which error codes are being thrown. A mechanic will be able to tell you if there is an issue with your ECM or another component.
Engine Stalling or Misfiring
Erratic engine behavior is another common symptom of a bad or failing ECM. A faulty computer can also be responsible for engine stalling or misfiring, though this tends to be more intermittent. These symptoms may come and go, and may appear to have no pattern to their severity or frequency.
Engine Performance Problems
When the ECM is faulty or failing, it will throw off the timing of fuel settings of the engine. You may notice unexplained drops in fuel efficiency, or you may feel your vehicle struggling to shift. Any sudden change in your vehicle’s performance is reason enough to seek out the source of the problem.
Related: What Are Car Diagnostics and What Do They Do?
Car Won’t Start
Another common symptom of a bad or failing ECM is a vehicle that will not start or struggles to start. If the ECM fails entirely, your car is left with no engine management control system, and as a result will not start. The engine may crank, but will not start without the vital inputs from the computer.
Related: What’s In a Tune-Up?
What to Do If You Think the ECM is Failing
Other systems might be causing deeper problems that need investigation.
Get your car checked by an expert mechanic.
It is important to note that all of these symptoms can be symptoms of other system failures or issues with your vehicle. But, since the ECM plays such a vital role in the performance of the vehicle’s performance, any issues which arise can be catastrophic to the engine. Computer systems found in modern cars are extremely complex, sophisticated, and complicated – this makes it tricky to diagnose and troubleshoot computer related problems.
If you suspect that your ECM is the source of your worries, you should have the vehicle inspected by a trained professional. Catching this issue early on can save a lot of money and stress. Replacing this part can be a major expense, but fortunately, an ECM can be repaired or reprogrammed in many cases. This prevents you from having to replace the part entirely.
At AAMCO Colorado, we want to help! If your car has experienced any of the symptoms noted above, you may want to get ahead of the situation by identifying problems early on and getting them fixed. Book an appointment with your local Colorado AAMCO automotive maintenance and repair center today.
Good Day, I have a 2001 ford ranger 4.0 V6 4×4. The truck stalls while driving and speedometer stop working when stalls, sometimes starts and stalls no check engine light also no scan codes. Checked fuel pump, relays, fuses, wire connections. Wondering could it be ecu.?
Dale,
While we can’t diagnose your exact car & problem online, we would love to have you visit one of our AAMCO Colorado service centers, where our expert mechanics will run a full AAMCO Vehicle Courtesy Check on your vehicle to diagnose the issue and get you back on the road in no time.
Thanks, AAMCO Colorado
Got an 05 mustang v6 4.0, starts fine and runs fine, but driving down the road all lights, power windows, locks will just stop working. Could this be the ecm?
My ECM went out left me stranded if I buy a new ECM do I have to reprogram it or if I get an older one from a different Nissan it’s an 06 put it in do I have to reprogram it are flashing appreciate your help with this problem
If the ecm is going bad can a diagnostic test be ran to get an accurate diagnosis
Anthony,
We suggest asking your question through our Ask a Mechanic feature, and a real mechanic can get back to you soon. Or, if you are local, stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle.
Thanks,
AAMCO Colorado
Steve,
We suggest asking your question through our Ask a Mechanic feature, and a real mechanic can get back to you soon. Or, if you are local, stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle.
Thanks,
AAMCO Colorado
Victoria,
We suggest asking your question through our Ask a Mechanic feature, and a real mechanic can get back to you soon. Or, if you are local, stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle – our mechanics are experts and have experience dealing with failing ECM’s.
Thanks,
AAMCO Colorado
Good evening, I am hoping to get someone to tell me I’m not crazy, In 2011 I bought a 2007 Cadillac srx with 8,330 miles on it . Crestview in West Covina. I paid 33,690.00 for my beautiful car. Well I believe it was a buy back and the Polk report showes 15 repairs, service road calls and 2 closed recalls. One of them is a incorrectly programmed ECM that has caused me nothing but money since 23,000 miles. Gm nor the dealer will do anything about it and it was in many dealers shops under warranty but never fixed. New transmission 6 months ago now it needs a valve cover. Can’t sell it. What do I do
Kendall,
We know it can be frustrating not knowing what is wrong with your car. AAMCO is here to help! We suggest asking any specific questions through our Ask a Mechanic feature, and a real mechanic can get back to you soon. Or, if you are local to Colorado stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle where we can access any repair needs your vehicle may have.
Thanks,
AAMCO Colorado
I have a 2000 lincoln ls 3.9 the e light is on and transmission light.i get all gears but 1.2.and 3.and it’s like something is holding it back as I try to accelerate.could it possibly be a bad ecm
Teresa,
This could certainly indicate a problem with your ECM, or another transmission issue. Unfortunately, we can not diagnose your vehicle without seeing it in one of our service centers. If you are local to Colorado stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle where we can access any repair needs your vehicle may have.
Thanks,
AAMCO Colorado
My question is what if a different year ECM was put into a different year of the actual car will the transmission work properly. A 2012 ECM was put into a 2009 vehicle
Laurie,
It would be best to talk to a trusted mechanic about whether or a different ECM compatible with your car. Unfortunately, we can not diagnose your vehicle without seeing it in one of our service centers. If you are local to Colorado stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle where we can access any repair needs your vehicle may have.
Thanks,
AAMCO Colorado
1995 Buick Park Ave with only 95,000 miles. Car started throwing codes showing bad ECT and TTS on scanner Both show 304 degrees even on a cold engine. Now I also get a bad PDNL switch occassionally meaning car won’t start without multiple attempts. Cruise contol is out and traction control sometimes turns off. I have checked every wire on the car and they seem fine. Do you think this could be an ECM failing and causing what I think are bad codes Would the MEM-CAL be ok to put into a replacement ECM or should I try and replace that also?
Ronald,
This could be an indication of your ECM failing, or possibly other issues within your car’s electrical system. Unfortunately, we can not diagnose your vehicle without seeing it in one of our service centers. If you are local to Colorado stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle where we can access any repair needs your vehicle may have.
Thanks,
AAMCO Colorado
My 2012 Lincoln Navigator will stop when driving. Will restart again after you pull over. This will happen at all speeds. Could this be my emc. Thank you
James,
If your car stops driving at random times, this can indicate a variety of problems including serious transmissions issues. Unfortunately, we can not diagnose your vehicle without seeing it in one of our service centers. If you are local to Colorado stop by one of 14 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle where we can access any repair needs your vehicle may have.
Thanks,
AAMCO Colorado
hello i have a 1983 oldsmobile cutlass supreme the check engine light is on can you guys work on that old of a car i bought a new computer and the check engine light is still on with no codes……….. thanks………….
Robert,
We are happy to work on cars of any year. If you are local to Colorado stop by one of 15 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle where we can access any repair needs your vehicle may have. If you have additional questions, be sure to check out our “Ask a Mechanic” feature, where you can email in your question to one of our AAMCO Colorado mechanics.
Thanks,
AAMCO Colorado
My 2007 Hummer h3 runs fine but is having problems cranking. After driving for a few minutes and cut the Hummer off it doesn’t want to crank for like 10 minutes. Can you tell me what this could be? Computer vs fuel system or ignition
Lori,
Unfortunately, we can not diagnose your vehicle without seeing it in one of our service centers. If you are local to Colorado stop by one of 15 Colorado AAMCO Service centers and we can perform a free diagnostic check on your vehicle where we can access any repair needs your vehicle may have. If you have additional questions, be sure to check out our “Ask a Mechanic” feature, where you can email in your question to one of our AAMCO Colorado mechanics.
Thanks,
AAMCO Colorado
Idle air control does not work when engene gets warmed up. 2005 grandcherokee 3.7 liter.
I just had a brand new ECM in my 2003 Toyota Rav4. I am still having issues but not like I was having before. The codes that were active was P0755,P0758. Will these issues stop after driving the car as after awhile.
my car won’t shut off and the key out