Code
P1689
BUICK
P — Powertrain
Delivered Torque Circuit Fault
AI status
Completed
Completed
100%
Causes
- Open, short or high-resistance wiring in the Delivered Torque circuit
- Corroded, loose or damaged connector(s) between modules
- Failed PCM, TCM or other control module that transmits/receives the torque signal
- Faulty torque sensor or related actuator (electronic throttle, torque management module)
- Intermittent CAN-bus or LIN-bus communication problem
- Software/calibration issue or required module reprogramming
Symptoms
- MIL (Check Engine Light) illuminated
- Reduced engine power or 'limp' mode
- Transmission abnormal behavior or reduced shift functions
- Poor or inconsistent acceleration
- Stored freeze frame and trouble code P1689 (manufacturer-specific)
What to check
- Read DTCs and freeze frame data with a manufacturer-level scan tool; note related codes
- Verify battery voltage and charging system health
- Perform visible inspection of wiring and connectors for damage, corrosion, or looseness
- Scan live data for Delivered Torque (and related parameters) while cranking and under load
- Check CAN/LIN bus status and look for communication errors
- Wiggle-test wiring and connectors while monitoring live data for intermittent changes
Signal parameters
- Delivered Torque value often appears as a percentage or Newton-meters in live data (expected: stable, realistic values relative to throttle and load)
- If an analog sensor is used, expect a 0–5 V signal range or industry-specific voltage reference
- CAN message IDs and valid message frequency (no missing or corrupted messages)
- Reference and ground voltages at the sensor and module (battery voltage and 0 V ground)
Diagnostic algorithm
- Retrieve all stored codes and freeze frame. Note ignition state, engine speed, and load when code set.
- Verify battery voltage (12.4–12.9 V resting; >13.5 V charging) and good grounds. Repair if low.
- Visually inspect wiring and connectors between PCM, TCM, torque sensor/actuator, and related components. Repair damaged harness or corrosion.
- With a scan tool, monitor Delivered Torque and related parameters while operating the engine. Recreate symptom if safe.
- Perform continuity and resistance checks on suspect circuits. Check for shorts to power or ground and open circuits.
- Check CAN/LIN communication: view bus errors, message frequency, and related module responses. Repair bus faults.
- If wiring and connectors are good, test or swap the torque sensor/actuator if service information permits.
- If all external components check good, follow manufacturer procedures to test/replace or reflash the PCM/TCM.
- Clear codes and perform a road test to confirm repair. Monitor for recurrence and verify no additional codes appear.
Likely causes
- Wiring harness damage at common wear points or repair areas
- Moisture or corrosion at connectors for PCM/TCM or torque sensor
- Failed or intermittent module (PCM or TCM)
- Loose battery terminal or poor chassis/body ground affecting signal reference
Fault status
Status
Delivered Torque circuit fault detected. Module reports open/short/out-of-range or communication failure for the delivered torque signal. MIL stored and drivability protections may be active.
Repair difficulty: Medium
Diagnostic time: 1.5-4.0 hours
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