P2638

Code

LAND ROVER P — Powertrain

Torque Management Feedback Signal A - Range / Performance

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 17 EN: 32 RU: 22

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Page language: EN

Causes

Damaged, corroded or loose connector for the torque feedback sensor/actuator
Wiring open, short to ground or short to battery in the feedback signal circuit
Faulty torque management feedback sensor or related actuator (throttle/torque sensor/position sensor)
Poor or missing ground or power supply to the sensor/actuator
Intermittent connection (broken wire or terminal)
ECM internal fault or corrupted software/calibration

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Reduced engine power or limp‑in mode triggered
Poor throttle response, hesitation or surging
Intermittent drivability issues that may correlate with wiring movement
Stored P2638 (may be accompanied by additional torque/throttle codes)

What to check

Read and record fault codes and freeze‑frame data with a scan tool; note conditions when the fault set
Check for additional related DTCs (throttle/boost/transmission)
Visually inspect wiring, connectors and terminals for damage, corrosion or looseness at the sensor/actuator and ECM
Backprobe the feedback signal connector and monitor live data/PID for the Torque Feedback A signal while operating the engine (key on/run and varying load)
Check sensor/actuator power supply and ground circuits for proper voltage and continuity
Perform wiggle test on harness while monitoring live signal for intermittent changes

Signal parameters

Type: electrical feedback signal (typically a voltage signal referenced to ECM ground)
Expected electrical range: typically within 0–5 V (varies by model); should change smoothly with torque/throttle demand and not be stuck at a single value
Failure signatures: signal stuck high or low, intermittent spikes/dropouts, erratic or no change with throttle/load
Compare live PID values to the ECM expected behavior and thresholds from OEM data

Diagnostic algorithm

Connect a capable scan tool, record P2638 and any related codes, and capture freeze‑frame data. 2. Verify battery voltage is stable (no low voltage conditions). 3. Inspect sensor/actuator connector and wiring visually; repair obvious damage. 4. Backprobe the feedback signal, power and ground pins with the engine running and vary load; confirm the signal changes smoothly and stays within expected range. 5. Perform continuity/resistance checks from the sensor connector to the ECM connector to find opens/shorts, using OEM wiring diagrams. 6. Wiggle harness and connectors while watching live data to expose intermittent faults. 7. If wiring and connectors are good, test or substitute the torque feedback sensor/actuator per manufacturer procedure. 8. If component replacement does not correct the fault, consider ECM diagnosis or software update as directed by OEM. 9. Clear codes and road‑test to confirm repair; recheck for reoccurrence and additional stored faults.

Likely causes

Connector contamination or bent pins at the feedback sensor/actuator
Broken or chafed wiring between sensor/actuator and ECM
Failed torque feedback sensor/actuator (electrical failure)
Faulty ground or supply to the sensor circuit

Fault status

⚠️ Status

Torque Management Feedback Signal A — Range/Performance. ECM detected an out‑of‑range or inconsistent torque feedback signal; engine may be in reduced power until repaired.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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P2638 — Torque Management Feedback Signal A - Range / Performance