P0978 Fault Code

Shift Solenoid C Control Circuit Range/Performance

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0978 fault code indicates a problem with the Shift Solenoid C Control Circuit, which can result in issues with the transmission shifting performance. The solenoid controls the flow of transmission fluid to facilitate the proper engagement of gears, allowing for smooth gear changes and optimal performance of the vehicle's drivetrain.

What are the symptoms of the P0978 code?

Drivers may experience one or more of the following symptoms when the P0978 code is present:

• Harsh or slipping transmission shifts
• Delayed engagement when shifting gears
• Inability to shift into certain gears or stuck in one gear
• Transmission overheating due to improper fluid flow
• Dashboard warning lights, including the check engine light.

What causes the P0978 code?

Several factors can lead to a P0978 fault code, including:

• Faulty shift solenoid C
• Damaged wiring or poor connections in the control circuit
• Low transmission fluid levels, which can affect hydraulic pressure
• Issues with the transmission control module (TCM)
• A malfunctioning transmission coolant temperature sensor that can disrupt solenoid operation.

How to fix P0978?

To resolve a P0978 fault code, follow these steps:

• Begin with a thorough inspection of the wiring and connectors related to the shift solenoid C. Replace any damaged components.
• Check the transmission fluid level and condition, topping off or replacing it as needed.
• Test the shift solenoid C for proper operation using a multimeter and replace it if found faulty.
• If the issue persists, consider checking the transmission control module and other related sensors for faults.