What does it mean?
P1682 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Powertrain Data Bus Implausible Message from ABS Control Module .
Symptoms
- MIL on together with ABS and stability control warning lamps
- Traction or stability control cutting in on dry roads with no wheel slip, or disabled completely
- Speedometer reading erratically or dropping to zero for a moment
- Harsh or delayed transmission shifts because wheel speed data is not trusted
- Cruise control refusing to engage or dropping out
- Occasional unexpected brake intervention that the driver can feel
Likely causes
- Faulty wheel speed sensor circuit sending an impossible value
- Damaged reluctor ring, or rust and debris at a wheel speed sensor tip
- Mismatched tyre sizes, a wrong-size spare fitted, or badly uneven tyre pressures skewing wheel speed data
- Excessive wheel bearing play letting the sensor gap vary
- ABS module internal fault or incorrect coding after replacement
- CAN wiring partially damaged or corroded near the ABS unit, corrupting the messages
- Low battery voltage or a poor ABS module power/ground upsetting its calculations
How to fix it
- Read the ABS module's own fault memory and freeze frame data alongside the engine module codes
- Compare all four wheel speed values on live data during a slow drive and look for one that drops out or reads differently
- Inspect wheel speed sensors, their connectors, cables and reluctor rings for rust, debris, cracks and bearing play
- Confirm tyre sizes, tread depths and pressures match across each axle, and check whether a temporary spare is fitted
- Check battery voltage and the ABS module power and ground with voltage-drop tests
- Inspect the CAN wiring near the ABS unit for corrosion and chafing, and verify the module coding if it was replaced
- Clear both memories, road test and re-scan to see which fault returns first