P2642
Torque Management Feedback Signal "B" Range/Performance
- Severity
- Medium
- Driving
- Drivable — book it in
Torque management feedback signal "B" is present but implausible - the reduction reported does not match what was asked for. That usually means the engine module is not delivering what it was asked, rather than that the signal path is broken.
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 in the module 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
Computer output circuits and control module
P2600P2601P2602P2603P2604P2605P2606P2607P2608P2609P2610P2611P2612P2613P2614P2615P2616P2617P2618P2619P2620P2621P2622P2623P2624P2625P2626P2627P2628P2629P2630P2631P2632P2633P2634P2635P2636P2637P2638P2639P2640P2641P2642P2643P2644P2645P2646P2647P2648P2649P2650P2651P2652P2653P2654P2655P2656P2657P2658P2659P2660P2661P2662P2663P2664P2665P2666P2667P2668P2669P2670P2671