C1408

DTC C1401-C1408 or C1413-C1416

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 Descriptor

DTC C1401: Right Front Wheel Speed Sensor Circuit Malfunction

DTC C1402: Left Front Wheel Speed Sensor Circuit Malfunction

DTC C1403: Right Rear Wheel Speed Sensor Circuit Malfunction

DTC C1404: Left Rear Wheel Speed Sensor Circuit Malfunction

DTC C1405: Right Front Wheel Speed Sensor Circuit Open or Shorted

DTC C1406: Left Front Wheel Speed Sensor Circuit Open or Shorted

DTC C1407: Right Rear Wheel Speed Sensor Circuit Open or Shorted

DTC C1408: Left Rear Wheel Speed Sensor Circuit Open or Shorted

DTC C1413: Right Front Wheel Speed Sensor Malfunction

DTC C1414: Left Front Wheel Speed Sensor Malfunction

DTC C1415: Right Rear Wheel Speed Sensor Malfunction

DTC C1416: Left Rear Front Wheel Speed Sensor Malfunction

Diagnostic Fault Information









Circuit/System Description

The wheel speed sensor receives ignition voltage from the electronic brake control module (EBCM) and provides a DC square wave signal back to the module. As the wheel spins, the EBCM uses the frequency of the square wave signal to calculate the wheel speed.

Conditions for Running the DTC

C1401, C1402, C1403, and C1404

The ignition is in the ON position.

C1405, C1406, C1407, and C1408

^ The ignition is in the ON position.
^ Vehicle speed of 20 km/h (12 mph) or more

C1413, C1414, C1415, and C1416

^ The ignition is in the ON position.
^ Vehicle speed of 20 km/h (12 mph) or more

Conditions for Setting the DTC

C1401, C1402, C1403, and C1404

The EBCM detects a rapid change in the wheel speed which is determined to be unreasonable.

^ The EBCM detects low output voltage of the wheel speed sensor for 15 seconds or more (for 2WD).
^ The EBCM detects low output voltage of the wheel speed sensor for 30 seconds or more (for 4WD).

C1405, C1406, C1407, and C1408

The EBCM detects one of the following conditions in the wheel speed sensor circuits:

^ An open
^ A short to ground
^ A short to voltage

C1413, C1414, C1415, and C1416

The EBCM detects noise in the wheel speed sensor signal for more than 5 seconds.

Action Taken When the DTC Sets

The following actions occur:

^ The EBCM disables the antilock brake system (ABS) for the duration of the ignition cycle.
^ The ABS indicator turns ON.

Conditions for Clearing the DTC

^ The condition for setting the DTC is no longer present and the ignition is cycled OFF.
^ The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

^ Inspect the encoder ring surface on the back of the wheel bearing for metal debris build up that could cause an erratic reading with the sensor. Do not use a magnet to clean the encoder ring, or damage may occur.
^ If 2 or more wheel speed sensors are inoperative diagnose each wheel speed sensor individually.
^ After repairs are made, and DTCs are cleared, operate the vehicle at speeds greater than 15 km/h (10 mph) to complete the self test, and the EBCM will turn off the ABS indicator.

If the customer comments that the ABS indicator is ON only during moist environmental conditions: rain, snow, vehicle wash, etc., inspect the wheel speed sensor wiring for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure:

1. Spray the suspected area with a 5 percent saltwater solution. To create a 5 percent saltwater solution, add 2 teaspoons of salt to 8 fl oz of water (10 g of salt to 200 ml of water).
2. Test drive the vehicle over various road surfaces: bumps, turns, etc., above 40 km/h (25 mph) for at least 30 seconds.
3. Rinse the area thoroughly when completed.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Wheel Speed Sensor parameter. The reading should be the same speed on all sensors when driving in a straight line at a speed greater than 20 km/h (13 mph).

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Ignition ON, test for less than 1 V between the low reference circuit terminals of the appropriate sensor listed below and ground.
^ Left front sensor circuit terminal 18
^ Right front sensor circuit terminal 6
^ Left rear sensor circuit terminal 4
^ Right rear sensor circuit terminal 16
-> If greater than the specified range, test the low reference circuit for a short to voltage.
3. Test for less than 1 V between the signal circuit terminals of the appropriate sensor listed below and ground.
^ Left front sensor circuit terminal 19
^ Right front sensor circuit terminal 7
^ Left rear sensor circuit terminal 5
^ Right rear sensor circuit terminal 17
-> If greater than the specified range, test the signal circuit for a short to voltage.
4. Ignition OFF, test for infinite resistance between the low reference terminal of the appropriate sensor listed below and ground.
^ Left front sensor circuit terminal 18
^ Right front sensor circuit terminal 6
^ Left rear sensor circuit terminal 4
^ Right rear sensor circuit terminal 16
-> If less than the specified value, test the low reference circuit for a short to ground.
5. Test for infinite resistance between the signal circuit terminal of the appropriate sensor listed below and ground.
^ Left front sensor circuit terminal 19
^ Right front sensor circuit terminal 7
^ Left rear sensor circuit terminal 5
^ Right rear sensor circuit terminal 17
-> If less than the specified value, test the signal circuit for a short to ground.
6. Ignition OFF, disconnect the harness connector at the wheel speed sensor.
7. Test for less than 1 Ohm between the appropriate low reference circuit terminals listed below.
^ Left front sensor circuit terminal 18 at the EBCM harness connector and terminal 1 at the wheel speed sensor harness connector
^ Right front sensor circuit terminal 6 at the EBCM harness connector and terminal 1 at the wheel speed sensor harness connector
^ Left rear sensor circuit terminal 4 at the EBCM harness connector and terminal 1 at the wheel speed sensor harness connector
^ Right rear sensor circuit terminal 16 at the EBCM harness connector and terminal 1 at the wheel speed sensor harness connector
-> If greater than the specified range, test the low reference circuit for an open or high resistance.
8. Test for less than 1 Ohm between the appropriate signal circuit terminals listed below.
^ Left front sensor circuit terminal 19 at the EBCM harness connector and terminal 2 at the wheel speed sensor harness connector
^ Right front sensor circuit terminal 7 at the EBCM harness connector and terminal 2 at the wheel speed sensor harness connector
^ Left rear sensor circuit terminal 5 at the EBCM harness connector and terminal 2 at the wheel speed sensor harness connector
^ Right rear sensor circuit terminal 17 at the EBCM harness connector and terminal 2 at the wheel speed sensor harness connector
-> If greater than the specified value, test the signal circuit for an open or high resistance.
9. If all circuits test normal, replace the wheel speed sensor. If the DTC resets, replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

^ Front Wheel Speed Sensor Replacement
^ Rear Wheel Speed Sensor Replacement
^ Control Module References for EBCM replacement, programming and setup