P2642: Torque Management Feedback Signal B Range/Performance

What it means

Torque management feedback signal B is outside its expected range or does not behave as expected.

At a glance

• Usually lights the check-engine light

How it works

The powertrain control module uses torque management feedback signal B to coordinate engine torque with other systems. P2642 is set when the received value is present but falls outside its expected range or changes in a way the controller does not expect.

Common causes

Most likely first.

1. Sender calibration drift
2. Bus value corrupted by EMI
3. Sensor element aged beyond calibration window

Symptoms

• Reduced engine power or torque
• Hesitation or sluggish acceleration

How to diagnose it

1. Save freeze-frame data and note the engine load and vehicle conditions when signal B was flagged.
2. Compare live data for torque feedback signal B with related torque request and response values to identify when they diverge.
3. Check for other module or communication codes that could affect the signal's source or delivery.
4. Inspect the relevant module connectors, grounds, and CAN wiring for damage, poor contact, or routing near sources of electrical interference.
5. Use the manufacturer's diagnostic procedure to assess the source module's calibration and signal behavior before replacing parts.

Common fixes

• Repair damaged or poorly connected network wiring or connectors.
• Correct wiring routing or shielding issues if testing confirms electrical interference is corrupting the value.
• Update or recalibrate the source module when the manufacturer's procedure identifies calibration drift.
• Replace a faulty signal source module or sensor only after testing confirms it is outside its calibration window.

Can I keep driving?

If the vehicle remains predictable, a short, gentle trip may be possible, but reduced torque or hesitation can make traffic maneuvers risky. Avoid hard acceleration and arrange diagnosis soon.