P078C - OBD Trouble Code

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Is your shift timing solenoid working slow? Do you see the P078C error code often? This is a common type of error code which appears in most of the vehicles with few exceptions. Solenoids are electromagnetic pistons which controls the hydraulic pressure and helps in assisting the transmission. If the TCM finds the solenoid to be faulty, then P078C error code will be stored in the vehicle.

The malfunction indicator lamp will be illuminated when the Engine control module finds that there is one or more issue with the shift solenoid or its circuit. The error code may arise due to mechanical or electrical problem depending on other codes that are active in the system. If the transmission control module finds out that shift solenoid does not perform properly or if there is any other general malfunction in your vehicle, then it will set the P078C error code in the vehicle.

What causes this problem with the Shift Timing Solenoid B Low?

• Automatic transmission fluid is unclean.
• The timing of the shift solenoid is faulty.
• Lessen ATF.
• ATF has blocks in the passage.
• TCM is defective.
• ECM might be faulty.
• Wire connections are damaged.
• Molten pins/ connectors.

1. Shift Solenoid - Replace the faulty or broken shift solenoids so that they perform properly and can avoid P078C error code.
2. Shift Valves - Is this component damaged or broken? Don’t worry, you can find the right replacement for shift valves at an affordable cost online.
3. Engine Light - If the engine light is too bright, then it is a good idea to replace them immediately.
4. Transmission Filter - Check the transmission filter if there are any blocks. If you find so, clear them off. 
5. Transmission Valve Body - Check for damages or faults in this component. If they are defective replace them to avoid P078C error code in your system.
6. Connector - The terminals of the connectors must be damage free to avoid error codes. If you find them damaged, replace them as soon as possible.
7. Powertrain Control Module - A defective PCM can cause P078C error code in your car. Change them immediately.

For us our customers are everything, and that’s why we will help you to diagnose P078C code by mentioning some important symptoms below:

Common Symptoms

• Gears are blocked.
• Rough shifts.
• Transmission lithers.
• Shift timing is not prolific.
• Drivability problems.
• Bad acceleration.
• Decline in the performance.

After you know the symptoms of your vehicle’s problem, it becomes easy to detect it and get started with solving it. So, next on our list is few common steps to correct this issue with your vehicles:

• Shift solenoids/ shift valves have to be replaced.
• Transmission filter has to be free from blocks.
• The defective PCM/ connectors needs replacement.

Apart from this, you might need to replace other damaged parts too like shift solenoid, shift valves, engine eight, transmission filter, transmission valve body, connector, wiring, powertrain control module and more. You can easily find all these parts with us. Not only that you can get these parts shipped to your door free, if your cart value happens to exceed $99.

Here are some steps which you should follow in order to diagnose this fault code:

• Firstly, inspect the Automatic transmission fluid for proper and clean fluid and see if the levels are correct or overfilled. In case the liquid is dirty, it is always best to remove and refill them and remove the blockages. If you have driven your vehicle to 30,000 to 60,000 miles and still don’t remember when you lastly changed the fluid, this can be one of your problem as you would have focused on your maintenance schedule.
• Do the symptoms still pop up despite the fluid being good? Then you have to check the shift solenoids depending on your vehicles model and make. Also, don’t fail to check the connectors and wiring harness for damages. Repair them as needed.
• Now thirdly check your shift timing solenoid? Carry out the resistance test where you connect the pins in the solenoid and measure it with a help of multimeter to check the electrical integrity. Mechanical operation test can also be verified by applying voltage manually to the solenoid. This information will be available in your service manual.
• Test the transmission control module / engine control module so as to check if the functionality of the sensor and circuit are performing good by carrying out the same test as above. But the pins must be connected to the transmission control module / engine control module.

Common Mistakes When Diagnosing the P078C

• Flawed TCM.
• Lessened fluid in transmission.
• Transmission shift solenoid substandard.
• Broken transmission valve body.
• Problematic cables.