P0764
Shift Solenoid C Intermittent
When a vehicle powertrain module registers the fault code P0764, it points directly to an internal system malfunction identified as "Shift Solenoid C Intermittent". Operating your engine under this condition may degrade long-term fuel maps.
Driver's Summary
Storing code P0764 is your car's way of telling you something is wrong with the shift solenoid c intermittent. On the road, this usually shows up as random harsh shifts, check engine light turns on and off. The vehicle is usually drivable, but the root cause needs attention soon to avoid more expensive repairs down the road.
Symptoms
Random harsh shifts, check engine light turns on and off
Common Causes
- Loose electrical connection to Solenoid C
- Solenoid failing intermittently when hot
- Frayed wire shorting randomly
- Dirty transmission fluid
How to Fix
- 1 Secure transmission connectors
- 2 Replace Shift Solenoid C
- 3 Perform a wiggle test to locate wiring break
- 4 Change transmission fluid
Technical Explanation
The PCM triggers P0764 after its internal monitoring routine detects that a specific circuit or sensor has exceeded its acceptable operating range. The TCM compares the ratio between input turbine speed sensor and output speed sensor readings against the expected gear ratio stored for each commanded gear position. A deviation greater than a few percent indicates clutch slippage, solenoid malfunction, or internal mechanical failure. Once confirmed, the code is stored as a permanent DTC and the MIL is activated. The freeze frame snapshot — recording RPM, load, coolant temperature, and fuel trim at fault detection — is also saved and is critical for accurate diagnosis.
Is It Safe to Drive?
You can drive short distances, but the symptoms — random harsh shifts, check engine light turns on and off — indicate the affected system is compromised. Leaving this unresolved will lead to progressively worse fuel economy and potential damage to components beyond the original fault.
Mechanic's Pro Tip
For P0764, test the solenoid's coil resistance with a multimeter before ordering parts — most solenoids should read between 14 and 40 ohms; an open (infinite resistance) or short (near zero) confirms it's failed electrically. Also verify the PCM is commanding the solenoid by backprobing the connector with a test light during the relevant operating condition — if there's no command signal, the fault is in the PCM or wiring, not the solenoid itself.
Solenoid and fluid: $250 - $500