P0702 OBD-II Trouble Code: Transmission Control System Electrical

P0702 code definition

Storage of a P0702 trouble code signifies that the Powertrain Control Module (PCM) has detected a problem with the automatic transmission control system. Related trouble codes include P0700 and P0701.

What the P0702 code means

A P0702 trouble code means that one of the transmission's sensors, solenoids, or switches has sent a signal to the PCM of the detection of a reading that doesn't match the manufacturer's specifications. In addition, the PCM can store a P0702 trouble code when other transmission-related trouble codes are stored.

What causes the P0702 code?

Some of the more common causes of a P0702 trouble code include the slippage of a transmission component, failure of the torque converter clutch, and shift solenoid failure. A low fluid condition in the transmission can also cause the storage of a P0702 trouble code to the PCM. Faulty sensors, solenoids, or switches can cause a P0702 trouble code, as well as any faulty wiring or connectors.

What are the symptoms of the P0702 code?

Some of the symptoms often associated with a P0702 trouble code include:

• No visible symptoms
• Transmission failure
• Slipping of the transmission
• Overheating of the transmission
• Difficulty shifting
• Failure to shift
• Engine stall when coming to a stop

How does a mechanic diagnose the P0702 code?

To properly diagnose a P0702 trouble code, a mechanic needs a suitable code reader, a manufacturer's wiring schematic, and a digital volt/ohmmeter. The mechanic should also perform the following when diagnosing the code:

• Visually inspect the wiring and connectors to the PCM, using the manufacturer's wiring schematic for guidance.
• Connect the scanner to the diagnostic connection to download any freeze frame data and stored trouble codes.
• After all wiring, connectors, and components have been replaced or repaired, the mechanic should clear the code and take the vehicle for a test drive to see if the code returns.

Common mistakes when diagnosing the P0702 code

A common misdiagnosis is for the mechanic to rebuild the transmission and replace the torque converter in the belief that this can fix the problem. Oftentimes, a fix is as simple as replacing a faulty component or wiring.

How serious is the P0702 code?

A P0702 trouble code, if left unfixed, can lead to catastrophic failure of the transmission, especially in a low fluid condition. A mechanic should attempt to fix and clear other trouble codes related to the transmission before trying to fix this code, since this code is sometimes associated with other transmission-related codes.

What repairs can fix the P0702 code?

With a P0702 trouble code serving as an informational code for other more specific problems, dealing with the other codes first can often fix and clear the code. If the code returns after fixing all other transmission problems, the mechanic should attempt the following repairs:

• Repair any damaged wiring, connectors, or components.
• Rebuild the transmission, perform a fluid flush, and replace the torque converter if the transmission has suffered extreme damage for a low fluid condition that was allowed to go on for too long.
• In addition, in a low fluid condition, fill the transmission to an appropriate level to fix any leaks. Afterward, the mechanic should fill the transmission with fluid to the appropriate level.
• Replace any faulty sensors, solenoids, or switches.
• Replaced the hydraulic pump if the problem lies there.
• Replace the PCM if faulty or this code is stored in a vehicle with a manual transmission.

Additional comments for consideration regarding the P0702 code

The storage of a P0702 trouble code is an indicator of more specific transmission problem and usually precedes the storage of a more specific transmission-related trouble code. This code is specific to vehicles with an automatic transmission, and if found on a vehicle with a manual transmission, it indicates a faulty PCM.

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