Many things go into the successful operation of the traction control system. For example, the ABS system not only pulses the brake on spinning wheels to eliminate slip. But the ECU can also cut fuel supply and adjust the timing to momentarily reduce engine power, and help to restore traction. If the vehicle has a P0858 DTC, it means that there is a low voltage signal coming from the traction control system, and this can negatively impact its performance.
How Serious is the Code?
In terms of severity, a P0858 diagnostic trouble code ranks extremely high. The presence of this engine error code can result in the failed operation of the traction control system, which can severely impact the safety of your vehicle.
Symptoms of a P0858 include:
- Traction control system has stopped working
- Delayed, harsh or erratic shifting
- Limp mode
- Damaged wiring or corroded connectors
- Defective traction control switch
- Defective electronic brake control module/ABS module
- Defective traction control module
How to Diagnose the Code?
The first thing that should be considered when diagnosing a P0858 OBDII trouble code, is the condition of the wiring and connectors. If there is an on/off switch for the traction control, it should be examined for signs of water damage, and corroded or broken connectors. Should the problems be found, the traction control module and possibly ABS module will need to be tested.
What Repairs Will Fix P0858?
- Repair or replace damaged wiring and/or connectors
- Replace traction control switch
- Replace traction control module
- Replace electronic brake control module / ABS control module