C1258

DTC C1258: 4WD Switch Circuit Faulty






Circuit Description
During 2 wheel drive operation, 4WD switch is open (off), switched ignition voltage is applied through 4WD indicator lamp and sent to ECM (PCM) and monitored by EBCM.
When the operator selects 4 Wheel Drive, 4 Wheel Drive switch is closed (on), ECM respond by grounding 4 Wheel Drive circuit, which will illuminate 4WD indicator lamp. EBCM will sense that voltage is pulled low on the 4WD lamp circuit, indicating vehicle is in 4WD.

DTC Detecting Condition
DTC C1258 will be set when EBCM detects voltage on 4 Wheel drive input circuit is neither high (near 12 volts for 2WD) nor low (under 1 volt for 4WD). DTC C1258 will be set when voltage on the 4WD request circuit is between 5.25 volts and 3.36 volts at any time.

Action Taken When the DTC Sets
- ABS relay opens, removing power from the pump motor and solenoids.
- DTC C1258 is stored.
- ABS disabled, ABS warning light turns on.

Diagnostic Aids
Typical Causes of DTC C1258.
- Poor terminal connection at EBCM.
- Faulty ECM (PCM).
- Faulty EBCM.
- High resistance between ECM and EBCM.

DTC Troubleshooting





Steps 1 - 7





Steps 8 - 12

NOTE: "ABS Check: Type 1" must be performed first before using this flow.