Code
P1765
DAEWOO
P — Powertrain
Torque reduc. sig. ct mal
AI status
Completed
Completed
100%
Causes
- Broken, frayed, or shorted wiring in the torque reduction signal circuit
- Poor or corroded connector or pin contact at the TCM/ECM or inline connector
- Faulty torque reduction switch/sensor or related solenoid/actuator
- Faulty TCM or ECM internal input/output
- Low battery/charging system voltage or poor ground connection
- Intermittent connection due to vibration or water intrusion
Symptoms
- Check Engine / Transmission warning lamp illuminated
- Transmission slips or shifts harshly; possible limp-in (reduced gears)
- Reduced engine torque or drivability issues during shifts
- Intermittent loss of acceleration or hesitation
- Stored freeze-frame data related to transmission events
What to check
- Scan for P1765 and any related codes; record freeze-frame and live data
- Verify battery voltage and charging system health (avoid low-voltage false faults)
- Visually inspect wiring and connectors from engine harness to transmission for damage, corrosion, or water
- Backprobe the torque-reduction signal connector with key ON and during a monitored shift event
- Perform wiggle test on harness while monitoring the signal for intermittent faults
- Check grounds and power feeds to TCM/ECM
Signal parameters
- Type: Generally a digital on/off signal (command or status) between ECM and TCM
- Inactive level: near 0 V (ground) or low-voltage state
- Active level: vehicle dependent; typically a pull-up to system voltage or 5 V logic (consult OEM diagram)
- Behavior: signal may be a steady level during torque reduction or a timed pulse during shift events
- Always confirm expected voltage and waveform with the vehicle-specific service manual
Diagnostic algorithm
- Retrieve fault code(s) and freeze-frame. Clear codes and attempt to reproduce; note when P1765 returns.
- Check battery voltage and charge; ensure good battery/ground connections before further testing.
- Perform a visual inspection of the transmission harness, connectors, and moisture seals; repair obvious damage.
- Using an appropriate scan tool, monitor the torque-reduction input/output while commanding shifts (if supported).
- Backprobe the signal wire at the transmission connector and at the module connector. Measure voltage with key ON and during operation; look for expected changes or pulses.
- Check continuity between the transmission connector pin and the TCM/ECM pin. Repair open or high-resistance circuits.
- Inspect and test related grounds and supply voltages to the module. Clean or repair grounding points as needed.
- If wiring and connectors are good, test or replace the torque-reduction switch/solenoid/actuator per OEM procedure.
- If component substitution is not possible and wiring checks are normal, consider module reprogramming or replacement after verifying with OEM service information.
- After repair, clear codes and perform a road test to confirm the fault does not return.
Likely causes
- Open or shorted signal wire between ECM and TCM
- Corroded connector at the transmission harness
- Failed torque-reduction switch/solenoid or actuator
- Ground or supply fault affecting the signal
- Module communication or internal fault
Fault status
Status
Torque reduction signal circuit malfunction detected. Possible open/short/poor connection or failed component affecting the torque reduction command; may cause reduced torque or transmission limp mode.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Repair manuals
Manual library for DAEWOO
75
Browse 75 DAEWOO manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
DAEWOO
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DAEWOO: 2001
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- CDX, 4D Wagon, Standard
- SX, 4D Hatchback, Automatic
- SX, 4D Hatchback, Standard
- SX, 4D Sedan, Automatic
- SX, 4D Sedan, Standard
- SX, 4D Wagon, Automatic
- SX, 4D Wagon, Standard
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