P2644: Torque Management Feedback Signal High
The P2644 code indicates that the Engine Control Module (ECM) has detected a high voltage signal from the torque management feedback circuit. This circuit monitors the torque reduction request from the transmission control module (TCM) during shifts. A high signal suggests a short to voltage, faulty wiring, or a malfunctioning torque management solenoid or sensor. This can lead to harsh shifts, reduced fuel economy, and potential transmission damage if ignored.
1. Most Common Causes
- Short to voltage in the 'B' torque management feedback circuit wiring
- Open circuit in the signal or reference wire
- Corroded, damaged, or loose terminals in the electrical connector
- Faulty internal transmission torque management solenoid or sensor
- Failed transmission control module (TCM) or powertrain control module (PCM/ECM)
- Low or degraded transmission fluid level or condition
2. Symptoms You Will Notice
- Check Engine Light on
- Harsh or delayed transmission shifts
- Reduced fuel economy
- Transmission stuck in limp mode
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and record freeze frame data.
Step 2: Visually inspect wiring and connectors for damage, corrosion, or shorts.
Step 3: Test the torque management solenoid resistance and compare to specs.
Step 4: Check voltage at the feedback signal wire with key on, engine off; should be within 0.5-4.5V.
Step 5: If wiring and solenoid are OK, suspect ECM/TCM fault and perform further diagnostics.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause harsh shifts and potential transmission damage. Limp mode may activate, limiting speed.
How much does it cost to fix?▼
Repair costs vary from $150 for a simple wiring fix to $400 or more for solenoid or module replacement, including labor.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.