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Error Code P0614 is defined as ECM / TCM Incompatible. This means there’s an error in the compatibility between the vehicle’s ECM (engine control module) and TCM (transmission control module), which is likely caused by corrosion, or bad PCM.
This is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system, especially those made since 1996 up to present. It’s more common among Audi, Ford, Nissan, Mazda, Volvo, and Volkswagen. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another.
When Error Code P0614 is stored, that means there’s a problem within the compatibility between the PCM (powertrain control module, also known as ECM or engine control module in other vehicles) and the TCM.
In some cases, the TCM and ECM may be separate from each other. Newer vehicle models nowadays integrate the two into a single module (PCM), increasing the effectiveness of the controller and saving automakers space, time, and money.
Every time the ignition is turned on and the PCM is energized, multiple controllers conduct their self0test. Aside from running internal controller self-test, the CAN (controller area network) is used to compare the signal from each individual module, ensuring the function and interaction of various controllers.
If the PCM detects a discrepancy in monitoring its compatibility with the TCM, then Error Code P0164, while simultaneously activates the Check Engine light. Depending on the severity of the condition, multiple failures may be necessary before the Check Engine light activates.
Common symptoms for this code include drivability issues, such as:
- No start condition
- Engine stalls
- Erratic transmission shift patterns
- Harsh transmission shift patterns
- Inaccurate or inoperable speedometer or odometer
In some cases, other related codes may be present.
There are several reasons behind this code, such as:
- Bad PCM
- Corrosion at the connector
- Short or open in the wiring harness
- Loose ground strap at control module
- Fault in ground bus
- Insufficient control ground
- Faulty TCM
- ECM/TCM Programming error
- Failed PCM power source
How to Check
This code is one of the many tricky codes to diagnose and fix, even with professional technicians. Also, reprogramming issue must also be considered. Without the right reprogramming equipment, it will be impossible to replace a defective controller and complete the repair.
If there are other ECM/PCM codes present, then they must be addressed first before diagnosing P0164.
Start the diagnosis by connecting the OBD-II scanner, read the codes stored in the PCM and see if any related codes may be the root of the problem. After reading all saved codes, do a visual inspection of all circuits and wirings. Check the connectors and wirings using an ohmmeter to ensure there is no open or short circuit.
Then, check the PCM, CAN bus, and other relevant components.
When trying to diagnose this code, refer to your information source or TSB (technical service bulletin); looks for signs and symptoms parallel to the stored code. Search for the year, make, model, and engine of your vehicle. If you are able to find the right TSB, then you may get the best diagnostic information for your problem.
Use vehicle information source to obtain component locations, connector face views, connector pin-out charts, wiring diagram, and diagnostic flow chart related to your vehicle’s error code.
Then, use the DVOM to the test controller power supply fuses and relays. Next, test and replace any blown fuses as necessary. Fuses must be tested with circuit loaded.
If all fuses and relays are running well, check whether the controller related wiring and harness are in order. You may also want to check chassis and engine ground junctions. Again, use your vehicle information source to obtain ground locations as related circuits. Test ground integrity using the DVOM.
Then, check the system controllers for any signs of water, heat, or collision damage. Any controller that is damaged, especially by water, is considered defective and must be replaced.
If controller power and ground circuits are intact, then there’s a good chance the controller is defective, or there’s a programming error in the controller. Thus, controller replacement requires reprogramming. In some cases, you may want to get aftermarket reprogrammed controllers. Some vehicles and controllers require on-board reprogramming that may be done only through the dealership or a qualified shop.
How to Fix
The most common repair for this code is replacing the PCM. Other repairs include:
- Repair or replacement of faulty connectors, wiring, or the entire section of wiring harness
Error Code P0614 is a serious problem that can leave you stranded. Also, it leads to unreliable engine operation and an increase in fuel consumption. Thus, it’s important to have this problem fixed as soon as possible.