P2549
Torque Management Request Input Signal "B" Range/Performance
- Severity
- Medium
- Driving
- Drivable — book it in
Torque management request input "B" is present but implausible - the reduction being asked for does not make sense in the conditions. That usually points at the module making the request rather than at the engine module receiving it.
Possible causes
- CommonWiring or bus fault between the modules
- CommonCorroded connector at either module
- CommonLow battery voltage dropping a module off the bus
- CommonFault in the transmission, ABS or traction control module
- PossibleSoftware mismatch after a module replacement
- RareFailed control module input
What you might notice
- Harsh or erratic shifting
- Traction control warning light
- Reduced power
- Hesitation during gear changes
- Check engine light on
What to check, in order
- Read all codes across every module the tool can reach. Torque management is a conversation between modules, so the fault is often at the other end.
- Check battery voltage and state of charge - a weak battery causes module communication faults with no wiring problem at all.
- Inspect the connectors at both modules.
- Ask whether a module was recently replaced or updated. A software mismatch produces exactly this and no amount of wiring diagnosis will find it.
- Check the wiring between the modules for damage.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Vehicle speed control, idle control and auxiliary inputs
P2500P2501P2502P2503P2504P2505P2506P2507P2508P2509P2510P2511P2512P2513P2514P2515P2516P2517P2518P2519P2520P2521P2522P2523P2524P2525P2526P2527P2528P2529P2530P2531P2532P2533P2534P2535P2536P2537P2538P2539P2540P2541P2542P2543P2544P2545P2546P2547P2548P2549P2550P2551P2552P2553P2554P2555P2556P2557P2558P2559P2560P2561P2562P2563P2564P2565P2566P2567P2568P2569P2570P2571P2572P2573P2574P2575P2576P2577