P0766

Code

GWM P — Powertrain

- The solenoid switch D is not adjusted correctly.

Brand: GWM

Type: P — Powertrain

Views: UK: 0 EN: 1 RU: 3

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Page language: EN

Causes

Faulty shift solenoid D
Wiring harness damage, connector corrosion or poor connection at solenoid
Low, dirty, or incorrect transmission fluid
Contaminated or clogged valve body/solenoid filter
Stuck valve or internal transmission mechanical problem
TCM/PCM software or calibration issue

Symptoms

Check Engine / Transmission warning light (MIL) illuminated
Harsh, delayed, or erratic upshifts or downshifts
Transmission may be stuck in a single gear or enter limp/limitation mode
Reduced driveability or hesitation under acceleration
Unusual transmission noises or slipping under load

What to check

Read DTCs and freeze-frame data with a capable scan tool; note drive conditions when DTC set
Check for additional transmission-related codes
Inspect transmission fluid level and condition (color, smell, contamination)
Visually inspect connector at solenoid D for corrosion, bent pins, or water intrusion
Wiggle test wiring harness while monitoring fault status / live data
Measure supply voltage and ground at the solenoid connector with ignition ON and while cranking

Signal parameters

Control signal: PWM duty-cycle or switched ground from TCM/PCM (varies by design); when commanded ON the solenoid control pin typically approaches battery voltage or ground depending on driver type
Electrical: expect near-battery voltage on supply side and switching on control side; exact voltages and PWM frequency vary by model—refer to GWM service data
Resistance: solenoid coil resistance should match factory specification (check service manual) — significant deviation indicates open/shorted coil
Response: when commanded, solenoid should change hydraulic pressure/shift state promptly; long lag or no change indicates hydraulic/mechanical fault

Diagnostic algorithm

Verify code: Connect scan tool, record freeze-frame, clear codes and perform a test drive to see if P0766 returns.
Check fluid: Verify correct fluid type, proper level and condition. Replace or top-up if contaminated or low.
Visual inspection: Check connector at solenoid D and wiring harness for damage, corrosion or water intrusion; repair as needed.
Electrical tests: With ignition ON, measure battery supply at solenoid connector and check continuity to TCM/PCM ground. Backprobe control pin and measure while commanding solenoid with scan tool.
Coil resistance: Disconnect solenoid and measure coil resistance; compare to factory spec. Replace solenoid if out of range or intermittent.
Functional test: Command solenoid ON/OFF with scan tool while monitoring transmission behavior and pressure (if pressure gauge available). Confirm solenoid changes state.
Inspect valve body: If electrical checks pass but performance is poor, drop oil pan/valve body or remove solenoid(s) to inspect screens, bores and valves for contamination or sticking. Clean or replace as required.
Adjustment/calibration: If solenoid is adjustable or there is an adaptation/learn procedure, perform the specified adjustment or TCM adaptation/learn per GWM service instructions after repairs.
Software: Check for TCM/PCM software updates or technical service bulletins that address solenoid D faults; reflash if required.
Final verification: After repairs and any adaptations, clear codes and perform a full road test to confirm the fault does not return.

Likely causes

Solenoid D coil open, shorted, or intermittent
Poor electrical supply or ground to solenoid D (broken wire, corroded terminal)
Hydraulic passage blocked or filter clogged causing solenoid/valve misadjustment
Solenoid installed incorrectly or adjustment procedure not completed after service
PCM/TCM needs adaptation/learn procedure or software update
Internal valve body wear or sticking valve that prevents pressure control

Fault status

⚠️ Status

P0766 — Shift Solenoid D not adjusted/performance fault detected. TCM has detected that solenoid D is not responding or cannot be regulated to expected parameters; check solenoid, wiring, hydraulic circuits, and perform required adjustment or adaptation.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours

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P0766 — - The solenoid switch D is not adjusted correctly.