• Transmission slipping or not shifting properly
• Check Engine Light illuminated
• Poor fuel economy
• Faulty shift solenoid C
• Wiring issues such as damaged wires or poor connections
• Faulty transmission control module (TCM)
Shift Solenoid: An electromechanical valve that controls the flow of transmission fluid.
TCM: Transmission Control Module, the computer that controls the transmission.
• P0978
• P0980
This means that something is wrong with a part in your car that helps it change gears. It's like if a toy robot's arm won't move because the wire controlling it is broken or not getting power.
The code P0979 indicates a problem with the electrical circuit that controls the shift solenoid C in the transmission. The circuit is reading a low voltage, which means the solenoid may not be functioning properly.
P0979 is triggered when the transmission control module (TCM) detects a low voltage condition in the control circuit for shift solenoid C. This solenoid is responsible for controlling the flow of transmission fluid to engage specific gears. A low circuit condition can be caused by wiring issues, a faulty solenoid, or a problem with the TCM itself.
• Use an OBD-II scanner to confirm the code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the shift solenoid C for proper operation.
• Repair or replace damaged wiring or connectors.
• Replace the shift solenoid C if faulty.
• Replace or reprogram the TCM if necessary.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $400
Moderate
• Honda Accord
• Toyota Camry
• Ford F-150
• Regular transmission fluid changes
• Routine vehicle maintenance
• Inspect wiring and connectors periodically
Transmission Control Issue
• Avoid driving the vehicle if it's not shifting properly.
• Consult a professional mechanic for a thorough diagnosis.
Check your vehicle's warranty; transmission components may be covered under powertrain warranty.
P0979 has been a common issue in vehicles with electronic transmission control systems, particularly in models from the early 2000s.
Moderate – Address the issue soon to avoid potential transmission damage.
Driving with a malfunctioning transmission can be dangerous. Ensure repairs are conducted by a qualified professional.
• Vehicle at operating temperature
• Transmission in drive mode
Shift solenoid C is typically located inside the transmission, accessible by removing the transmission pan.
Q: Can I drive with a P0979 code?
A: It's not recommended to drive with this code as it can cause further damage to the transmission.
Q: How do I reset the Check Engine Light after repairs?
A: You can reset the light using an OBD-II scanner after fixing the issue.