Code
P0749
GWM
P — Powertrain
- Pressure Solenoid Malfunction
Views:
UK: 3
EN: 3
RU: 3
AI status
Completed
Completed
100%
Causes
- Faulty pressure control solenoid (electrically or mechanically)
- Open/short or intermittent wiring between TCM/ECM and solenoid
- Corroded/loose connector or poor ground
- Low, degraded, or contaminated transmission fluid
- Clogged valve body screen or internal hydraulic passages
- Sticking pressure regulator/valve in the valve body
Symptoms
- MIL (Check Engine/Transmission) illuminated
- Harsh, delayed, or erratic shifting
- Transmission slipping or poor engagement
- Torque converter lockup problems or shudder
- Vehicle may enter limp/limited transmission mode
- Abnormal/no rise in transmission line pressure under load
What to check
- Read and record DTC(s) and freeze frame data with a scan tool
- Inspect transmission fluid level, color, and smell (burnt smell or dark color indicates contamination)
- Visually inspect solenoid connector and harness for damage, corrosion, or loose pins
- Check for related codes (TCM/TC) and TSBs for manufacturer-specific fixes
- Backprobe solenoid connector to confirm supply voltage and ground while cranking/idling
- Measure solenoid coil resistance with multimeter and compare to specification
Signal parameters
- Typical supply voltage: ~11–14 V (key ON/engine running) to the solenoid feed
- Solenoid coil resistance: commonly ~6–40 Ω (manufacturer-specific — check spec)
- Controller command: PWM duty cycle 0–100% (varies with load/gear)
- PWM frequency: commonly 20–300 Hz (vehicle-specific)
- Line pressure: varies by vehicle and load — should rise with increasing duty cycle/engine load
Diagnostic algorithm
- Connect a professional scan tool, read and record DTC P0749 and any related codes; note freeze frame data and pending codes.
- Inspect transmission fluid: level, color, odor; correct level if low and inspect for metal debris. Replace fluid/filter if contaminated.
- Visually inspect wiring and connector at the pressure control solenoid for damage, corrosion, bent pins and secure fit; repair as needed.
- With ignition ON (engine off), measure solenoid coil resistance and compare to manufacturer spec; replace solenoid if out of range.
- Backprobe connector with engine running and observe supply voltage and solenoid control signal with a DVOM/scan tool/scope; confirm proper 12 V feed and TCM-driven PWM/ground switching.
- Wiggle test harness while monitoring data to check for intermittent faults.
- If electrical signals are correct but pressure is incorrect, measure transmission line pressure with a gauge across operating conditions; compare to spec.
- If line pressure is low or erratic and wiring/solenoid test good, disassemble valve body to inspect for clogged screens, debris, or stuck pressure regulator/valves; clean or replace valve body components as required.
- If wiring and hydraulic components test good, consider TCM/ECM fault or software — verify software level and perform reflash or replacement per manufacturer guidance.
- After repairs, clear codes, perform relearn procedures if required, and road-test to confirm repair.
- Safety notes: use appropriate PPE, support vehicle safely, transmission fluid is hot — avoid burns, and follow manufacturer service procedures.
Likely causes
- Failed pressure control solenoid (coil short/open or stuck valve)
- Damaged connector or pin corrosion at solenoid harness
- Low/contaminated fluid causing solenoid/valve sticking
- Internal valve body contamination or stuck pressure regulator
Fault status
Status
P0749 — Pressure control solenoid malfunction detected. Control circuit or hydraulic pressure out of spec; MIL on; transmission performance may be affected.
Repair difficulty: Medium
Diagnostic time: 1.5-4.0 hours
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