The powertrain control module is the central part of a car’s engine, it controls all of the engine’s functions including acceleration, braking, and more. This module also controls the fuel supply to the engine, and it monitors all of the sensors around it to make sure that everything is running smoothly.
Because of the importance of the powertrain control module, when it’s faulty your car might not even start at all. In this article, you will learn how to test a PCM on a ford car or any other car just as mentioned here on Cookip.
How To Test a PCM on a Ford
- 1 How To Test a PCM on a Ford
- 1.1 How to Fix a Bad PCM
- 1.2 Symptoms of a Bad PCM
- 1.3 How to Test a PCM With a Multimeter
- 1.4 How to Bench Test a PCM
- 1.5 How To Use OBD II To Test a PCM
- 1.6 How Much Does it Cost to Replace PCM
- 1.7 Common PCM Error Codes
- 1.8 What happens if PCM goes bad?
- 1.9 Is a PCM and ECM the same thing?
- 1.10 Conclusion
There are many ways to test a PCM relay with the most common way is by using a voltage meter.
To test the relay using a voltage meter, first, connect the red lead to the positive terminal and black lead to the negative terminal of the battery. Next, touch the probes together and then touch them on one of the pins of the relay. If there is no reading on your voltmeter then your PCM relay is faulty and needs to be replaced.
If your car is being difficult to start, the powertrain control module (PCM) might be faulty, so how can you tell when PCM is bad or what are the symptoms read on to find out all.
Gone are does days when all parts of the car are manually checked and operated. In most modern-day vehicles, everything ranging from the air intake and setting of timing is all carried out by one system which is the Powertrain control module.
How to Fix a Bad PCM
Unlike the alternator, fuel pump, filter, radiator, and motor starter, the Powertrain control module is not a mechanically built component. The PCM is an electronically operating computer chip.
Remanufacturing in this case usually means testing the computer, isolating and repairing any faults that may be found, then retesting the computer to make sure everything works correctly.
Symptoms of a Bad PCM
Remember, the powertrain control module is generally a combined controller consisting of the engine control unit (ECU) and the transmission control unit (TCU). The PCM commonly controls more than 100 factors in a car or truck.
When the PCM fails to perform any of the functions it is responsible for, then it is faulty and needs to be checked. Below are some signs that indicate a bad PCM
- Check engine light on
- Other warning lights on, on the dashboard
- Increased fuel consumption
- Difficulty in starting
- Inability to shift between gears
- Erratic movement
- Car stutters when starting
- Rough idling
The powertrain control module literarily controls ignition timing, fuel delivery, and valve timing in engines with Variable Valve Timing). The emissions functions, turbo boost pressure in turbocharged engines, idle speed, throttle position, and cruise control are not left out either.
If your car is suffering from any of the above-mentioned symptoms, your PCM might be faulty and if you know how to test PCM it will be a good advantage to you. Well if you do have the knowledge visiting a professional for checks is a good decision.
How to Test a PCM With a Multimeter
A PCM can be tested with a multimeter this process is used to measure the amount of current passing through to the PCM from the battery at a time. A good and properly charged battery should read at least 12.6 volts with the engine off, or 13.7 volts with the engine running.
If it is measuring Volts lesser than 12 Volts then your battery is faulty, therefore it is not sending the current amount of current to the PCM. A weak battery is enough to stop your car from starting, yes you read it right a weak battery would not let your engine run.
Generally, the engine depends greatly on the battery to run thereby making your vehicle drive. In a general, sense, when the ignition switch is turned on, it sends a signal to the motor starter to crank the engine. The starter depends on the current from the battery to turn and crank the engine.
It’s almost the same in an automatic car with PCM, except that in an automatic vehicle, when the ignition is turned on the PCM read the signal and sends it to different sensors to start the engine. After a visual inspection, take a multimeter to measure your battery to make sure is not weak.
How to Bench Test a PCM
Testing a PCM when it is outside its normal set up inside the car is very difficult and it requires a lot of complex setups to replicate the car. However, it is not totally impossible as there are other means to bench test a PCM, one of which is through physical observation.
To bench test a PCM by visual observation, first, unscrew and remove it from the car and keep it on a bench. A quick visual inspection before you start losing the screws and getting it open might just do the work and everything would be back in other.
Make sure that your PCM is connected to your battery, and that there’s no rust on the PCM itself or on the battery wiring. The same visual inspection and checking rule should be applied when you want to test your PCM.
Reconnect any loose wires if necessary. If your PCM has experienced corrosion, you’ll have to skip to step 5 to see if it’s failed.
How To Use OBD II To Test a PCM
An OBD-II is is enough to get the code scanning job done nicely and easily. If you have an OBD code scanner go ahead and plug it into the car computer to check for error codes.
Plug the OBD scanner in, if you have the basic code and know the knowledge you can easily just read it yourself. If you do not understand what the code means go ahead and search it on google or click here to check through a list of OBD Engine codes our experts have put together.
If you cannot find the error code on our OBD code list you can go ahead and look it up on google. OBD scanner can be a very handful for detecting both mechanical and electrical problems since the codes can help localize whatever might be causing your car a PCM problem.
How Much Does it Cost to Replace PCM
After you might have carried out a visual inspection, battery voltage measurement, and OBD scan and everything checks to be fine, then replacement is the only choice you are left with. The PCM might be fried, at this point, you should try and get a new powertrain control module to get your car back and running.
When buying, ensure that the PCM is the correct version not just for your make and model, but for the same year as well. If it turns out that your PCM was faulty, you’ll immediately notice an improvement in performance.
Ensure that the PCM is the correct version not just for your make and model, but for the same year as well. If it turns out that your PCM was faulty, you’ll immediately notice an improvement in performance.
On The Blog
Common PCM Error Codes
The codes P0174, P0175, and P0176 are associated with the vehicle’s emission control system. In order to diagnose the problem, a scan tool is required as well as access to a diagnostic procedure for 1996-2000 gas engines.
In conclusion, the codes P0174, P0175 and 0176 represent emission control system problems that require a scan tool and diagnostic procedures for 1996-2000 gas engines.
- P0174: The powertrain control system is not in a PON (Power On/Off) state
- P0175: The PON module has detected an internal fault with the powertrain control unit
- P0176: A significant hardware problem has been detected in the powertrain control system.
What happens if PCM goes bad?
If PCM goes bad a lot of other things in the vehicle will malfunction as well because the PCM is not able to coordinate the components it should. For example, the Powertrain control module is responsible for measuring the amount of air taken in and then providing the right ratio of fuel to archive complete combustion.
Continuing to run a vehicle with a bad PCM could cause further damage. Because the PCM controls the emissions of your car, a failed emissions test or the presence of oddly colored or foul-smelling exhaust may be a sign that your PCM is going bad. A malfunctioning PCM will activate dashboard error lights.
Is a PCM and ECM the same thing?
The terms PCM (Powertrain Control Module), ECU (Engine Control Unit), and ECM (Engine Control Module) can sometimes be used as interchangeable generic phrases for the same thing – a control unit for the engine/transmission system.
So the answer to the question is PCM and ECM are the same thing is NO. they are two different components but are interdependent.
The power control module (PCM) controls engine control and transmission control modules. The PCM module is responsible for its engine transmission controlling module.
A failure in the PCM can be attributed to engine or transmission issues in your vehicle. Other very obvious PCM failure symptoms include Code Scanning, Inspecting wiring and sensors, Checking your battery, and Trying a replacement.
Due to daily usage, shaking, rough road, and vibrations of the engine some things tend to lose grip and fall from their positions. This happens well with wires and connectors.
Your PCM might be proving to be faulty all because of a weak connection or loose wire, reconnect any loose wires if necessary. If you have any questions on how to test PCM on a Ford please ask using the comments section.