OBDII Code P0702: Transmission Control System Electrical

When the Diagnostic Trouble Code (DTC) P0702 appears on your Bidirectional Scan Tools or an OBD II scanner, it indicates an issue with the electrics controlling the auto transmission. This generic error code is shared by all vehicles supporting OBD II protocols. 

Code P0702 typically doesn’t appear alone as it should be accompanied by another. Fixing that other issue usually resolves P0702 as well. Learn more about the causes, symptoms, and possible solutions to solve this particular error code below. 

P0702 Definition

When the Powertrain Control Module (PCM) logs a P0702 error code, it means that it has identified an issue with the ATC. Both P0700 and P0701 appearing on your OBD2 Scanner for DIY belong to the same group of problems.

 To put it simply, if your PCM displays a P0702 error code, those sensors, switches, or solenoids of the transmission have detected a reading that deviates from the manufacturer’s requirements. Also, the PCM can save a P0702 fault code with other transmission-generated fault codes.

Error code P0702: Causes, Symptoms & Diagnosis

Causes

The most typical reasons for the P0702 error are a slipping gearbox part, a faulty torque converter clutch, or a malfunctioning shift solenoid. The P0702 fault code can also be stored in the PCM as a result of a transmission with low fluid. Error code P0702 can be caused by defective wiring or connectors, as well as bad sensors, switches, and/or solenoids.

  • Wiring open/short condition
  • The solenoid or valve is stuck or broken.
  • Because of a lack of fluid, the transmission has begun to slip and the tires are spinning.
  • Issues with the hydraulic system
  • Recently discharged batter
  • The trouble with the torque converter.

Symptoms

It should be noted that the P0702 code may occur with no visible symptoms. However, when it does, you might notice one or more of these symptoms:

  • Failure of the transmission
  • Transmission’s continuous slippage
  • The transmission overheated
  • To put it simply, it’s hard to change.
  • Stagnation in change
  • Stall in the brakes causes the engine to die

Diagnosis

You’d need a reliable OBD II scanner like Autel Mk808 or a similar product, a quality multi-meter, and a wiring blueprint to properly diagnose this code. First, we need to put the car through its paces on the open road to allay fears and collect vital information.

Some third-party code readers only provide overall group codes rather than individual ones. The only people who should be able to interpret the subsystem codes in your car are certified mechanics with the right equipment.

Initially, you might try to erase the code. Make sure to record all active codes, take a screenshot of any data that will be deleted, and save any information from the initial road test before wiping the drive.

A malfunction or abnormality, like a stuck solenoid, valve, or errant sensor reading, could have triggered the codes if they cleared and don’t come back during the final road-driving test.

At this point, you’d need to run freeze frame data with a scanner like Innova 5510 that can help you reveal the particular condition and exact points where the code triggered. That’s why you need an OBD II scanner with the capability of freeze-frame data.

If the codes come back right away or keep coming back during road tests, you need to take a closer look at the circuit associated with the DTCs. Some connectors and solenoids will be inaccessible without first removing the transmission oil pan, therefore this may need accessing internal transmission components.

Common mistakes when the diagnosis P0702 code

When a mechanic makes a false diagnosis, he or she may decide to redo the transmission or get a new torque converter. In many cases, the problem can be solved by just replacing a single component or some defective wiring.

Don’t think the actual problems have been solved just because the code disappears after being cleared. It’s possible that a moderate issue will escalate. Clearing the code without solid repairs or replacements on the corresponding component may cause greater damage in the future.

How to fix obd2 code P0702

As the P0702 code only provides context for other, more specific faults, it is common for the P0702 to be fixed and the code cleared after those other codes have been addressed. The following repairs should be attempted by the mechanic if the code reappears after they’ve fixed all transmission-related problems:

  • Fix any broken wires, plugs, or other parts.
  • If the transmission has been severely damaged due to a prolonged low fluid condition, it must be rebuilt, the fluid must be flushed, and the torque converter must be replaced.
  • Finally, if the transmission is leaking and the fluid level is low, add fluid until the leak stops. The transmission should then be refilled to the correct level by the mechanic.
  • Those switches, solenoids, and sensors should be replaced if they are not working properly. They’re not expensive and you can solve problems caused by them easily.
  • If it turns out to be the hydraulic pump, you’ll need to get a new one. When left untreated, faulty hydraulic pumps can cause a more serious problem.
  • If this code is present on a manual transmission car, the PCM needs to be replaced. However, a thorough diagnosis would still need to be performed before taking any action like repair or replacement.

Tips to Avoid future

The storing of a P0702 issue code indicates a more particular transmission problem and typically precedes the storing of a more precise transmission-related trouble code. If this code appears on a car with a manual transmission, you might have a problem with the PCM, as it is intended only for automatic transmissions.

Either way, you should maintain your transmission properly to prevent this code from reappearing in the future. Performing a DTC scanning with the Best Foxwell Scanner on a regular basis can help you catch this code or the corresponding codes earlier before it develops into a more serious problem.

Verdict

When you get a P0702 code, you’re likely having transmission problems in your vehicle. Therefore, you’d need to deal with other transmission codes that come with P0702 before moving to those specific troubleshoots. A proper and thorough diagnostic with the help of freeze frame data analysis can help identify the actual problems and causes.