P2548 is the general fault on a second torque request channel, B, used when a further module besides the transmission may ask the engine for less or more torque. GM spells out who sits on channel B: in the ECM part of its 2017 table 17OBDG04 and again in 19OBDG03A, P2548 checks the traction torque and speed request coming from the electronic brake and traction control module. A failure is counted when the message's two's-complement protection value does not match, at least 10 of 20 samples, or when the rolling counter fails to step up, at least 6 of 10. The test runs with run/crank active for over 0.5 s, ignition above 6.41 V and no lost-communication code U0121; GM rates it Type B, two trips. Traction or stability intervention via the engine may then be limited. P2549 to P2551 are its narrower faults.
Medium severity. Can I keep driving?Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
Symptoms
- Check engine light after two trips (GM Type B)
- Traction or stability control warning lamp
- Reduced traction intervention on slippery roads
Most likely causes
- Data bus disturbance between brake module and engine module
- Brake/traction control module sends corrupted messages
- Weak battery or poor module power supply
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P2548 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 5: Speed and idle
- 48: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2548?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P2548?
The most common causes are: data bus disturbance between brake module and engine module; brake/traction control module sends corrupted messages; weak battery or poor module power supply.
Related codes
- P2549Torque Management Request Input Signal B Range/Performance
- P2550Torque Management Request Input Signal B Low
- P2551Torque Management Request Input Signal B High
- P2544Torque Management Request Input Signal A
- U0121Lost Communication with ABS Control Module
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.