P0764

Code

GWM P — Powertrain

- Malfunction of C solenoid switch

Brand: GWM

Type: P — Powertrain

Views: UK: 1 EN: 3 RU: 1

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Page language: EN

Broken, chafed or corroded wiring in the solenoid C circuit
Poor or corroded connector at the solenoid or TCM
Open or shorted solenoid coil
Faulty transmission control module (TCM) or powertrain control module (PCM) output driver
Low battery voltage, blown fuse or faulty relay feeding the transmission harness
Contaminated or internally failed solenoid (valve body issue)

Check Engine Light / Transmission MIL illuminated
Transmission may go into limp/limitation mode (reduced gears)
Harsh, delayed, or erratic shifts or inability to shift into specific gears
Transmission may stay in one gear or refuse to engage certain ratios
Possible diagnostic trouble codes related to other shift solenoids or pressure control

Read and record trouble codes, freeze frame and live data with a capable scan tool
Inspect connector at solenoid C and TCM for corrosion, bent pins or water intrusion
Visually inspect wiring along the harness for damage, chafing, or repairs
Check battery voltage and transmission power/ground fuses and relays
Measure coil resistance of solenoid C at the harness (with connector disconnected)
Check continuity between solenoid connector and TCM connector; check for shorts to ground/12V

Typical solenoid coil resistance (cold): approximately 10–35 ohms (vehicle-specific; check service manual)
Commanded signal: switched/grounded by TCM with PWM duty cycle (0–100%); not a steady analog voltage in many systems
When commanded ON: solenoid drive present as PWM/current rather than a fixed 12V; expected current typically 0.3–1.5 A depending on design
No significant voltage (
PWM frequency commonly in the range of tens to a few hundred Hz (varies by manufacturer)

Retrieve all stored codes, freeze frame and relevant transmission data using a scan tool; note related codes.
Clear codes and attempt to re-create fault with road test or activation tests while monitoring live data for solenoid C status/command and any anomalies.
Visually inspect solenoid C connector and wiring; repair any obvious damage and reseat connectors.
With ignition off, disconnect solenoid C connector and measure coil resistance across the solenoid pins; compare to spec. Replace solenoid if open/shorted or out of range.
Check for continuity between the solenoid connector and the TCM pins; check for shorts to battery and ground.
Check supply voltage and ground at the solenoid connector with ignition on; verify fuse/relay feeding transmission circuits.
Use a bi-directional scan tool to command solenoid C ON/OFF while monitoring voltage/current and transmission response; note if TCM can successfully command and if the solenoid responds.
If wiring and solenoid test good but no proper command, inspect/replace TCM or repair TCM output driver as directed by manufacturer procedures.
After repair, clear codes, perform a transmission relearn if required, and road test to confirm proper operation and that code does not return.

⚠️ Status

Transmission shift solenoid C circuit malfunction — electrical fault or improper solenoid response detected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.0 hours

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P0764 — - Malfunction of C solenoid switch