P2549
Torque Management Request Input Signal B Range/Performance
Powertrain control (torque management)
Generic OBD-II
Medium
What it means
P2549 means another control module asked the engine to change its torque output, but the "B" request signal the ECM received was outside the expected range. Modules such as the transmission or traction control send these requests, so the fault is usually in that requesting module, the shared wiring, or the connection between them.
Medium
Can I keep driving? Often drivable, but a module is requesting a torque change the ECM finds implausible — expect possible reduced power, harsh shifts, or limp mode, so diagnose soon.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or limp mode
- Harsh, delayed, or erratic gear shifts
- Hesitation or surging under acceleration
Common causes
Most likely first
- Faulty torque-reduction request signal from another module (e.g. TCM, ABS/traction)Likely
- Wiring or connector fault on the torque-request 'B' circuitCommon
- Poor connection or corrosion between the requesting module and the ECMCommon
- Requesting control module fault or software mismatchLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and scan all modules — the requesting module usually has its own codes.
- Identify which module sends the 'B' torque request and inspect its wiring/CAN circuit to the ECM.
- Check connectors between the modules for corrosion, looseness, or damage.
- Repair wiring faults and address any codes in the requesting module first.
- Clear the code and confirm the request signal reads within range.
FAQ
Quick answers
Is it safe to drive with P2549?+
Short term usually yes, but reduced power or a limp mode can appear without warning. Diagnose it before extended or high-load driving.
Can I just clear P2549?+
It will reset once the ECM again sees an out-of-range torque request; the underlying module or wiring issue must be fixed.
Related codes
Often seen with P2549
Read & clear P2549 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX