Code
P0750
GWM
P — Powertrain
- Malfunction of A solenoid switch
Views:
UK: 18
EN: 16
RU: 16
AI status
Completed
Completed
100%
Causes
- Open or short in the shift solenoid A wiring (connector, harness, chafing)
- Poor or corroded connector or pin at the solenoid or TCM/PCM
- Faulty shift solenoid A (coil open/short or internal failure)
- Failed PCM/TCM output driver
- Blown fuse or poor power/ground to the transmission control circuit
- Contaminated, low, or overheated transmission fluid affecting solenoid operation
Symptoms
- Check Engine / Transmission warning lamp illuminated
- Transmission may stay in one gear (limp mode) or have limited gears
- Harsh, delayed, or no shifts related to gears controlled by solenoid A
- Transmission may fail to shift into certain gears
- Possible diagnostic trouble codes related to other shift solenoids or transmission control
- Reduced drivability or poor fuel economy
What to check
- Scan for stored codes and freeze-frame data; note PID values and shift events
- Visual inspection of wiring harness and connector for the A solenoid (damage, corrosion, water intrusion)
- Check transmission fluid level, color and odor (burning) before electrical tests
- Verify battery voltage and main transmission fuses/relays
- Backprobe solenoid connector and measure resistance and voltage while commanding solenoid with a scan tool
- Check continuity between solenoid connector and PCM/TCM pin
Signal parameters
- Solenoid coil resistance: check vehicle-specific spec (typical range often ~5–40 Ω depending on design) — compare to spec
- Supply voltage at solenoid harness: ~battery voltage (~12–14.5 V) when fused feed present
- Control signal: driven by PCM/TCM as switched ground or PWM — duty cycle 0–100% depending on commanded state
- PWM frequency: varies by manufacturer (commonly tens to a few hundred Hz) — use oscilloscope to verify waveform
- Activation current: varies by solenoid (generally under a few amps) — verify with clamp meter if needed
Diagnostic algorithm
- Retrieve codes and freeze-frame with an OBD-II scan tool; record any related transmission codes and symptoms.
- Inspect transmission fluid level/condition; correct fluid level and refill if low or contaminated. Replace fluid/filter if severely contaminated.
- Visually inspect wiring and connector at the A solenoid and along the harness to the PCM/TCM for damage, corrosion, pin push-out, or water entry. Repair as needed.
- Verify power and ground to the solenoid circuit: check fuse/relay and measure battery voltage at the fused feed at the transmission harness.
- With ignition on (engine off) measure solenoid coil resistance across the solenoid terminals and compare to vehicle spec. Look for open or shorted coil.
- Backprobe control side with a multimeter or oscilloscope while commanding the solenoid with a scan tool. Verify PCM commands (voltage/drop to ground or PWM) and that the solenoid responds (current draw changes).
- Check continuity from solenoid connector to PCM/TCM pin to rule out wiring open/short. Wiggle test harness while monitoring for intermittent changes.
- If wiring and solenoid test as good but no proper control signal, test PCM/TCM output driver. If suspect, confirm with manufacturer procedures before replacing module.
- If solenoid is electrically good but shifting still incorrect, inspect valve body and internal transmission components for mechanical faults or blockage.
- After repair, clear codes and perform a road test while monitoring shift solenoid commands and transmission behavior. Re-scan for reoccurrence.
Likely causes
- Wiring/connectors to shift solenoid A damaged or corroded
- Faulty solenoid coil (open or short)
- Poor ground or supply voltage to transmission solenoid circuit
- Faulty TCM/PCM output driver (less common)
- Contaminated transmission fluid or internal valve body fault (lower probability than wiring/coil)
Fault status
Status
MIL on — Transmission fault recorded. Possible limp-in mode or limited gear operation until fault is resolved.
Repair difficulty: Medium
Diagnostic time: 1.5-3.0 hours
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