What is a PCM on a Chevy truck?

Asked By: Bala Graiño | Last Updated: 19th June, 2020
Category: automotive auto parts
4.4/5 (254 Views . 13 Votes)
The PCM, or powertrain control module, in your Chevy truck serves as the on-board diagnostic computer for your vehicle. The PCM controls everything from air-to-fuel ratio to generating fault or trouble codes for critical vehicle systems.

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Considering this, what are the signs of a bad PCM?

7 Common PCM Failure Symptoms

  • Your 'Check Engine' Light is On.
  • Your Car Won't Start or Starts Roughly.
  • Sudden Loss of Gas Mileage.
  • You Failed Your Emissions Test.
  • Your Engine Stutters or Stalls.
  • Erratic or Random Shifting.
  • You're Receiving a PCM-Related Error Code.
  • What to Do If You Experience PCM Failure Symptoms.

Additionally, how much does a PCM repair cost? Without this system working on top form, you can end up with a number of car problems. The cost of replacing your powertrain control module will be between $450 and $1,630. For labor, you can expect to pay between $45 and $125. Parts should cost you $400-$1,500.

Also to know is, what is PCM on a truck?

A power-train control module, abbreviated PCM, is an automotive component, a control unit, used on motor vehicles. It is generally a combined control unit, consisting of the engine control unit (ECU) and the transmission control unit (TCU). Most of them are oriented toward engine management and performance.

How do I reset my Chevy PCM?

How to Reset the ECM on a Chevy Truck

  1. Remove the nut from the negative battery cable using a socket set or wrench. Slide the cable off of the battery and set it aside.
  2. Turn the headlight switch to the "On" position to drain the ECM of any remaining power. Wait at least 10 minutes, then turn it back to the "Off" position.

34 Related Question Answers Found

How much does it cost to flash a PCM?

$60 is a reasonable price. As maxst said some dealers get $100 plus. It is just an update and the Diablosport Tuner will allow you to update to the latest CALID flash files for both the PCM and TCM.

What causes a PCM to go bad?

PCMs typically fail for one of two reasons: voltage overloads (often due to a short in a solenoid or actuator circuit) or environmental factors (corrosion, thermal stress or vibration). If water gets inside a PCM, it can short circuits and set up irreversible corrosion that ruins electronic connections.

How do I change my PCM?

Change Your PCM
  1. Go to the Beneficiary Web Enrollment (BWE) portal on the milConnect website.
  2. Click on the red "Log On" button at the top of the page.
  3. Click on the "Change Primary Care Manager" button in the Actions Menu.

Can the PCM cause transmission problems?

For example, poor performance or unexplained drops in fuel economy or efficiency are often related to onboard car computer problems, or faulty ECU issues. A damaged ECU can cause problems when shifting gears in an automatic transmission, or cause sudden jerking or stopping that's similar to transmission problems.

How do you troubleshoot a PCM?


How to Troubleshoot the PCM
  1. Locate your vehicle's PCM.
  2. Look specifically at the wiring harness.
  3. Locate your vehicle's diagnostic data port.
  4. Connect your OBD-II scanner to the diagnostic data port.
  5. Push your key into the vehicle's ignition cylinder.
  6. Watch the OBD-II device's read-out screen for the codes.

Will a car start with a bad PCM?

It is highly possible that symptoms of a bad PCM include the vehicle not running at all. All these components play a part in kicking off and running the engine. When they can't function properly, the car may not run at all. In that case, the engine will not crank or even if it does, it will not start.

Does a PCM need to be reprogrammed?

Reprogramming may be required for a variety of reasons. PCM Reprogramming is also necessary to change the engine idle speed, spark timing, fuel mixture or other emission control functions. PCM Reprogramming may be required to resolve a hot or cold starting issue, idle roughness, stalling, or an emissions failure.

How do you program a PCM?

Turn your car's ignition on, connect your scan tool to the OBD II connector on the PCM and then turn the scan tool to its "On" position. Depending on the make of your car, you will have to select several specifications regarding your vehicle (engine and fuel system details).

Will a bad PCM drain battery?

A failed ECM power relay can also cause a battery drain or dead battery. If the relay shorts it can leave power on to the computer, even when the vehicle is turned off. This will place a parasitic drain on the battery, which will eventually cause it to go dead.

What does a PCM look like?


The PCM (Powertrain Control Module) is the main computer in the automobile that controls all its functions. Although a PCM may look like a single unit from the outside, most contain a separate ECM and TCM, each with their own processor and programming ROM.

Does the PCM control the fuel pump?

Pulse-modulated fuel pumps control fuel pressure by changing the speed of the fuel pump. In brief, the PCM or the fuel pump control module changes the fuel pump speed by rapidly switching the fuel pump on and off.

Where is the PCM fuse located?

It is always a good idea to consult your vehicle's owner's manual to find the exact location of your Dodge's PCM, but typically they are found in the engine compartment, under the passenger floorboard, under the seats, or behind the kick panels.

What is PCM audio output?

Pulse-code modulation, abbreviated "PCM," is a form of digital signal that is used to represent analog data. Depending on the model of television you watch, switching the audio output to PCM may improve the sound quality of the television's speakers.

Can a PCM be repaired?

Most remanufacturers will not even attempt to repair a PCM if the vehicle it came out of was submerged in a flood. Replacement is the only option. Thermal stress and vibration can form microcracks in circuit boards (which are repairable).

What all does the PCM control?


What Is A Powertrain Control Module (PCM) In Cars? The PCM or Powertrain Control Module of your car is a critical automotive component or rather a combined control unit. The other subsystems controlled by PCM include the Fuel Injection, Fuel emission, Automatic transmission and Anti-lock brake systems and so on.

Will a bad ECM throw a code?

Engine performance issues are another symptom of a possible problem with the ECM. If the ECM has any issues, it may throw off the timing and fuel settings of the engine, which can negatively affect performance. A faulty ECM may cause the vehicle to experience a reduction in fuel efficiency, power, acceleration.

What is the difference between PCM and ECM?

So, the difference is that a 'PCM' controls both the engine and transmission system, whereas an 'ECU/ECM' or 'TCM' controls only one of these systems.