What it means
Torque management request input signal B is outside the expected range or does not behave as expected. The code alone does not identify the cause.
At a glance
- Usually lights the check-engine light
How it works
Torque management request input signal B carries a request for the powertrain control module to adjust engine torque. P2549 sets when signal B is present but its value or response falls outside the expected range or pattern, such as an invalid request from another module or a sensor signal that no longer tracks correctly.
Common causes
Most likely first.
- Requesting module sending invalid values
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
Symptoms
- Check-engine light
- Reduced or inconsistent engine power
- Altered transmission shifting
How to diagnose it
- Save freeze-frame data and observe live signal B while conditions change to see whether it is out of range, slow to respond, or inconsistent.
- Check for related codes from the module that supplies signal B, since those may explain invalid request values.
- Inspect the signal B sensor or switch mounting and connector for looseness, contamination, corrosion, or damaged wiring.
- With the correct wiring information, check whether signal B changes smoothly through its operating range and compare it with the manufacturer's specification.
- If the input and wiring behave correctly, check the requesting module's reported values and communication before replacing parts.
Common fixes
- Secure a loose signal B sensor or switch and clean contaminated contacts where applicable.
- Repair damaged signal B wiring or connector terminals.
- Replace a signal B sensor or switch that fails its range or response test.
- Correct the sending module fault if its reported request values are invalid.
Can I keep driving?
Cautious driving may be possible if power delivery and shifting remain consistent, but avoid towing and hard acceleration while torque requests may be misread. Stop if power or shifts become unpredictable.
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.