GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P1382: Wheel Speed Sensor Circuit Performance

DTC P1385: Wheel Speed Sensor Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Rough Road Sensor Signal

P1385

P1385

P1385

P1382

Low Reference

--

P1385

--

P1382

Circuit/System Description

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 or an electronic brake control module (EBCM), if equipped with the antilock brake system (ABS). The ABS 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 by the EBCM through 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.

Conditions for Running the DTC

    • DTCs P0501 and P1501 are not set.
    • The vehicle speed is more than 5 km/h (3 mph).
    • The DTCs run continuously when the above conditions are met.

Conditions for Setting the DTC

P1382

The ECM detects invalid data from the rough road sensor or the electronic brake control module (EBCM) for 30 seconds.

P1385

The ECM does not detect a rough road signal from the wheel speed sensor for 30 seconds.

Action Taken When the DTC Sets

DTC P1382 and P1385 are Type C DTCs

Conditions for Clearing the DTC

DTC P1382 and P1385 are Type C DTCs

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Drive the vehicle over 5 km/h (3 mph), DTCs P1382 or P1385 should not set.
  2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

    Important: If the ABS lamp is illuminated, the ABS system must be diagnosed prior to using this diagnostic procedure. Refer to Diagnostic System Check - Vehicle.

  1. Ignition OFF, disconnect the harness connector at the wheel speed sensor or the electronic brake control module (EBCM) - if equipped with ABS.
  2. Ignition OFF, test for less than 5 ohms between the low reference circuit and ground.
  3. • Wheel Speed Sensor (LR) low reference circuit terminal B
    • Wheel Speed Sensor (RR) low reference circuit terminal A
    • Wheel Speed Sensor (LF) low reference circuit terminal B
    • Wheel Speed Sensor (RF) low reference circuit terminal A
    If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  4. Ignition ON, test for 4.8-5.2 volts on the signal circuit.
  5. • Wheel Speed Sensor (LR) signal circuit terminal A
    • Wheel Speed Sensor (RR) signal circuit terminal B
    • Wheel Speed Sensor (LF) signal circuit terminal A
    • Wheel Speed Sensor (RF) signal circuit terminal B
    If less than the specified range, test the signal circuit for a short to ground or an open. If the circuit tests normal, replace the ECM.
    If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  6. If all circuits test normal, test or replace the wheel speed sensor or EBCM - if equipped with ABS.

Component Testing

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

  1. Ignition OFF, disconnect the harness connector at the wheel speed sensor.
  2. Notice: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.

  3. Raise and support the drive wheels.
  4. Engine running, place the transmission into 2nd gear or drive for an automatic.
  5. Test for 70 mV AC between the signal terminal and the low reference terminal.
  6. If less than the specified range, replace the wheel speed sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rough Road Sensor Replacement
    •  Control Module References for engine control module replacement, setup, and programming