Error Code P078D: What It Means & What To Do?

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Is the shift timing solenoid too high in your vehicle? Does the error code appear again and again? Most of the vehicle which are equipped with automatic transmission have this general type of error codes. The control and maintenance of the shift solenoid is done by the TCM. If the TCM finds out that the shifting time of the solenoid is high, then the P078D error code will be stored in the vehicle.

Controlling the hydraulic flow internally to assist the transmission is the main purpose of the solenoid. There are many solenoids that perform their operation internally and it might be difficult to say as which solenoid cause this error code. The malfunction indicator lamp will be lit if there is one more issue wither with the circuit of the solenoid. If the P078D error code is set, it means there is a malfunction within the circuit or the shift timing solenoid is too high.

What causes this problem with the Shift Timing Solenoid A High?

• Shift timing solenoid is broken.
• Automatic transmission fluid is murky.
• ATF is very low.
• Passage in ATF has blocks.
• Wiring harness is defective.
• ECM faces problems.
• TCM has issue.
• Connector or pin issue.

1. Shift Solenoid - Visually inspect this part for any damages or faults. If they are found to be defective, replace them at once.
2. Shift Valves - Are the shift valves causing trouble in your vehicle? Then it’s more likely to be defective which needs immediate change.
3. Engine Light - P078D code can be stored in your vehicle if the engine light illuminates. Replace them with the right part from Parts Avatar.
4. Transmission Filter - Are there any blocks or leaks? Then the blockages has to be removed and component has to be checked for leaks.
5. Transmission Valve Body - P078D error code can arise if this component is damaged. Try replacing them as preferred by manufacturer.
6. Connector - Connector terminals have to be safe without any damages. Replacing the damaged component is always a best choice.
7. Powertrain Control Module - A faulty or broken PCM needs to be fixed soon so as to avoid further occurrence of P078D error code.

Interested in knowing the symptoms to OBD code P078D? If yes, then you have arrived at the right place. We at Parts Avatar have listed out few common symptoms associated with this fuel injector problem.

Common Symptoms

• Gears are jammed.
• Shift is irregular.
• Shift timing is improper.
• Weak drivability.
• Acceleration is worst.
• Generally weak performance.

After understanding the symptoms and few common causes behind the OBD error code, we are here to help you out in understanding the ways and means to correct the issue. To solve any issue you need to follow certain steps, and to solve OBD error code P02CE, you will need to undergo the following replacements:

• Either the shift solenoids or shift valves needs to be changed.
• Removing blocks in the transmission filter.
• Defective PCM /connectors has to be changed.

Apart from the fuel injector, you might need to undergo few more replacements. You might need shift solenoid, shift valves, engine light, transmission filter, transmission valve body, connector, wiring, PCM and many other parts. Where to get them from? Well, if you want quality parts, then we can prove to be your dream destination.

It is essential to diagnose this fault code. Here are some steps which a mechanic should follow for diagnosing the problem that triggered a P078D code to be stored:

• It is always good to check the automatic transmission fluid. They should not be dirty, have bad odor or burnt smell and the level has to be correct. If not so, if not so, replace the dirty fluid with clean one and remove the blockages if there are any. The problem may rise in your vehicle if you had forgotten as to when you lastly changed the fluid and forgot to change them or you would have been busy with the maintenance schedules.
• Do the error codes keep appearing though the fluid is clean? Then you may have to externally check the solenoids, wiring harness and connectors depending on your vehicles model and make. If you find any damages or leaks, get them rectified.
• It is always a good idea to test the shift solenoids in several ways. You can check the mechanical operation of the vehicle by manually applying voltage to the solenoid. Resistance test can also be carried out to measure the resistance between the pins with the help of multimeter to check the electrical integrity. You can find this information in the vehicles service manual.
• Similar to the above test you have to test your TCM to check the functionality of the sensor/ circuit but the pins will be connected to the TCM/ECM. This test can help to check the integrity of the solenoid and the circuit as well.

Common Mistakes When Diagnosing the P078D

• Imperfect TCM.
• Decreased fluid in transmission.
• Transmission shift solenoid defective.
• Malfunctioning transmission valve body.
• Problem with cables.