Code
P0745
GWM
P — Powertrain
- Malfunction in the solenoid pressure circuit
AI status
Completed
Completed
100%
Causes
- Open or shorted solenoid electrical circuit (wiring or connector)
- Faulty pressure control solenoid (coil failure or internal short)
- Poor connector contact or corrosion at solenoid/TCM connector
- Blown fuse or faulty TCM power/ground
- Damaged transmission harness (pinch, chafe, rodent)
- Intermittent TCM or internal TCM driver failure
Symptoms
- MIL/Check Engine lamp on
- Transmission may enter limp/reduced-gear mode
- Harsh or delayed shifts, gear hunting
- Degraded transmission pressure regulation causing slip or clunking
- Possible stored transmission-related fault codes
What to check
- Read and record freeze frame and all stored/related codes with a scan tool
- Visually inspect transmission wiring harness and connectors for damage, corrosion, or water intrusion
- Check fuses and main power/ground to TCM
- Backprobe solenoid connector to observe control voltage and ground while cranking/with engine running
- Measure solenoid coil resistance with multimeter (unplug solenoid)
- Perform wiggle test on wiring while monitoring live data / DTC status
Signal parameters
- Typical solenoid coil resistance: ~10–40 ohms (vehicle-specific — consult service manual)
- Expected control voltage: battery voltage (11–14 V) to solenoid supply; control side uses switched ground or PWM from TCM
- PWM duty cycle: 0–100% (varies by commanded pressure); frequency commonly 50–300 Hz
- No-load current draw: generally 0.2–2.0 A depending on solenoid design
- Open-circuit: infinite resistance; short to ground: near 0 ohms
Diagnostic algorithm
- Connect a professional scan tool. Read and log P0745 and any related codes and freeze-frame data.
- Clear codes and perform a test drive or replication procedure to verify repeatability.
- Inspect harness and connector at the transmission solenoid pack and at the TCM for corrosion, bent pins, water damage, or mechanical damage.
- With ignition off, disconnect solenoid connector and measure coil resistance between solenoid pins. Compare to specification. If out of range, suspect solenoid.
- Check for continuity between solenoid connector and TCM connector (check both supply and control circuits). Repair any open circuits.
- With connector connected, backprobe the control wire. With engine running or commanded by scan tool, observe voltage/PWM and compare to expected parameters. Use an oscilloscope if possible to confirm waveform quality.
- Check TCM power and ground integrity and fuses/relays feeding the TCM/solenoid supply.
- If wiring and supply are good but solenoid shows abnormal resistance or does not respond to commanded activation, replace the solenoid/solenoid pack.
- If new solenoid still faults and wiring checks good, suspect TCM driver fault — confirm with manufacturer diagnostic procedures before replacing TCM.
- After repairs, clear codes, recheck live data and perform road test to ensure fault does not return.
Likely causes
- Wiring damage at harness near transmission or frame
- Corroded or loose solenoid connector
- Failed pressure control solenoid coil
- Blown fuse or poor battery/ground connection to TCM
- Faulty TCM driver (less common)
Fault status
Status
TCM detected an open, short, or invalid signal in the transmission pressure control solenoid circuit. The condition may set the MIL, cause limp mode, and lead to abnormal shifting. Troubleshoot wiring, connectors, solenoid, fuses, and TCM as needed.
Repair difficulty: Medium
Diagnostic time: 1.0 - 2.5 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email