Cruze

DTC P1392 or P1393

The engine control module (ECM) identifies engine misfire by detecting variations in crankshaft speed. Crankshaft speed variations can also occur when a vehicle is operating over a rough road. The ECM receives a rough road signal by a rough road sensor (wheel speed sensor). The rough road sensor can detect if the vehicle is on the rough surface based on wheel acceleration/deceleration data supplied by each wheel speed sensor. This information is sent to the ECM from the rough road signal circuit. The rough road sensor is a wheel speed sensor. The wheel speed sensor produces an alternating current (AC) voltage that increases with wheel speed. The ECM receives a rough road signal from a wheel speed sensor located at the left front wheel. The ECM can determine if the vehicle is on a rough road surface based on the signal from the wheel speed sensor. When the ECM detects a rough road condition, misfire diagnostics will be disabled.

P1392 00

The ECM detects that the rough road sensor voltage is less than 0.1 V.

P1393 00

The ECM detects that the rough road sensor output is greater than 4.9 V.

DTC P1392 00 and P1393 00 00 are Type C DTCs.

DTC P1392 00 and P1393 00 00 are Type C DTCs.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Engine Controls Schematics

Scan Tool Reference

Control Module References for scan tool information

Note: This procedure is for vehicles without ABS. If the wheel speed sensor harness is damaged in any way, DO NOT repair the harness.

1. Drive the vehicle over 5 km/h (3 MPH). Observe the DTC information with a scan tool. DTCs P1392 00 or P1393 00 should not set.
2. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

1. Ignition OFF, disconnect the harness connector at the B5LF Wheel Speed Sensor - Left Front.
2. Ignition ON, test for B+ on the rough road signal circuit terminal B and ground.

⇒	If less than the specified range, test the rough road signal circuit for a short to ground or an open/high resistance.

3. Ignition OFF, reconnect the B5LF Wheel Speed Sensor - Left Front.
4. Ignition OFF, disconnect the ECM X2 connector.

Note: You may have to rotate the left front wheel before the B+ voltage will be indicated.

5. Ignition ON, test for B+ at the ECM terminal 10 X2.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

6. If all circuits test normal, test or replace the B5LF Wheel Speed Sensor - Left Front.

Note: This procedure is for vehicles without ABS. If the wheel speed sensor harness is damaged in any way, DO NOT repair the harness.

Static Test

1. Ignition OFF, disconnect the harness connector at the B5LF Wheel Speed Sensor - Left Front.

Caution: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive shafts. Do not operate the vehicle in gear with the wheels hanging down at full travel.

2. Raise and support the drive wheels.
3. Engine running, place the gearbox into 2nd gear or drive for an automatic transmission.
4. Test for varying 8-12 V between the rough road signal terminal A and B+ voltage terminal B.

⇒	If less than the specified range, replace the B5LF Wheel Speed Sensor - Left Front.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.