What it means
The control module monitors torque management feedback signal A and sets this code when the reported value exceeds its expected level.
At a glance
- Usually lights the check-engine light
How it works
Torque management feedback signal A carries torque-related information used by engine or transmission controls to coordinate their actions. P2640 sets when the receiving module sees signal A above its expected level, such as when the source module reports an invalid high value or the bus message is stuck high.
Common causes
Most likely first.
- Source module sends invalid high value
- Signal stuck high on the bus
Symptoms
- Reduced engine power or torque
- Hesitation or sluggish acceleration
How to diagnose it
- Save freeze-frame data and review live data for torque feedback signal A to confirm whether it is high or remains fixed as operating conditions change.
- Scan all modules for communication faults and source-module codes that could explain an invalid high signal A report.
- Inspect the signal A source module's connectors and accessible network wiring for damage, corrosion, loose pins, or shorts.
- Compare signal A with related torque request and feedback values, if available, to determine whether only signal A is implausibly high.
- Test network continuity and the source module's power and grounds according to the manufacturer's wiring and diagnostic information.
Common fixes
- Clean and secure a corroded or loose signal A network connector.
- Repair damaged wiring or a short causing the bus message to stick high.
- Resolve a confirmed fault in the module sending torque feedback signal A.
- Replace a faulty module only after its network circuit, power, and grounds pass checks.
Can I keep driving?
A high torque feedback value can lead to reduced power or hesitation, so drive gently and avoid overtaking, steep climbs, and towing. Stop if the vehicle cannot maintain a safe speed.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.