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DTC codes / P07xx · Transmission / P0764

P0764Shift Solenoid 'C' Intermittent

P0764 indicates that the transmission control module (TCM) has detected an intermittent electrical fault in shift solenoid 'C', which is responsible for controlling a specific gear shift. The TCM monitors the solenoid's circuit and flags the code when the signal is erratic or momentarily lost, often due to a poor connection or failing solenoid.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaTransmission

Symptoms you may notice

  • Illumination of the check engine light or transmission warning light
  • Harsh or delayed gear shifts, especially when engaging the affected gear
  • Transmission may slip or fail to shift into certain gears
  • Intermittent shifting problems that come and go
  • Often no symptoms besides the warning light, as the fault may be momentary

Common causes, most likely first

  1. Faulty shift solenoid 'C' with an intermittent internal electrical failure
  2. Damaged or corroded wiring harness or connector at the solenoid
  3. Poor electrical connection at the transmission control module (TCM)
  4. Contaminated transmission fluid causing solenoid sticking or erratic operation
  5. Internal transmission mechanical issues affecting solenoid performance
  6. Loose or damaged ground connection for the transmission circuit

How to diagnose and fix it

  1. Check transmission fluid level and condition; top off or replace if contaminated
  2. Inspect the wiring harness and connectors at the solenoid for damage or corrosion
  3. Perform a resistance test on shift solenoid 'C' and compare to manufacturer specifications
  4. Check for continuity and shorts in the circuit between the solenoid and TCM
  5. Verify TCM connectors are secure and free of corrosion
  6. If electrical tests indicate a faulty solenoid, replace shift solenoid 'C'
  7. Clear the code and test-drive the vehicle to confirm the repair

Intermittent Solenoid Faults Often Misdiagnosed

  • An intermittent solenoid code can be set by a momentary voltage spike or drop, so the solenoid itself may still be functional; always check wiring and connections first.
  • Transmission fluid contamination is a common cause of intermittent solenoid operation, yet many technicians replace the solenoid without addressing the underlying fluid issue.
  • The TCM may set P0764 due to a poor ground connection, which can mimic a solenoid failure and lead to unnecessary replacement.
  • A failing transmission control module can cause intermittent solenoid codes, but this is rare and should only be considered after all other possibilities are ruled out.
  • Some vehicles use shift solenoid 'C' for multiple gears, so a fault may cause symptoms in more than one gear, complicating diagnosis.

Can I keep driving with P0764?

If the vehicle is shifting normally and the light is steady, you can drive cautiously to a repair shop, but avoid heavy acceleration or towing. If shifting becomes harsh or the transmission slips, stop driving to prevent further damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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