Circuit Description
As a toothed ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce an alternating current (AC) voltage signal whose frequency is proportional to the wheel speed. The magnitude of this signal is directly related to wheel speed and the proximity of the wheel speed sensor to the toothed ring often referred to as the air gap.
Conditions for Running the DTC
This test detects a short to battery, ground, or open in the left front wheel speed sensor circuit.
Conditions for Setting the DTC
| • | The wheel speed circuit is open or shorted to the battery or ground. |
| • | There is a loose connection in the wheel speed circuit. |
| • | The wheel speed sensor resistance is very high. |
| • | The electronic brake control module (EBCM) is malfunctioning. |
Action Taken When the DTC Sets
This is a critical operational fault. The antilock brake system (ABS) is disabled and the ABS warning lamp is turned on. The proportioning is operation.
Diagnostic Aids
Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.
The following are possible causes of the malfunction:
| • | A short to ground or a short to voltage in the wheel speed sensor circuitry |
| • | An open or high resistance in the wheel speed sensor circuitry |
| • | A malfunctioning wheel speed sensor |
| • | A malfunctioning wheel speed sensor rotor |
| • | An internal EBCM malfunction |
If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views | ||||
1 |
Is the resistance within the specified value? | 1.0-1.5 kohms | Go to Step 4 | Go to Step 2 |
2 |
Is the resistance within the specified value? | 1.0-1.5 kohms | Go to Step 4 | Go to Step 3 |
3 | Replace the wheel speed sensor. Is the repair complete? | -- | System OK | -- |
4 | Use a DVM to measure the resistance between terminal 14 of the EBCM harness connector, and terminal 1 of the left front wheel speed sensor harness connector. Is the resistance within the specified value? | less than 1 ohms | Go to Step 6 | Go to Step 5 |
5 |
Is the repair complete? | -- | System OK | -- |
6 | Use a DVM to measure the resistance between terminal 25 of the EBCM harness connector, and terminal 2 of the left front wheel speed sensor harness connector. Is the resistance within the specified value? | less than 1 ohms | Go to Step 8 | Go to Step 7 |
7 |
Is the repair complete? | -- | System OK | -- |
8 | Use a DVM to measure the resistance between ground and terminal 14 of the EBCM connector. Does the DVM show the specified value? | ∞ | Go to Step 10 | Go to Step 9 |
9 | Repair the short to ground in circuit DK BLU. Is the repair complete? | -- | System OK | -- |
10 | Use a DVM to measure the resistance between ground and terminal 25 of the EBCM connector. Does the DVM show the specified value? | ∞ | Go to Step 12 | Go to Step 11 |
11 | Repair the short to ground in circuit YEL. Is the repair complete? | -- | System OK | -- |
12 |
Is the voltage within the specified value? | 0 V | Go to Step 14 | Go to Step 13 |
13 | Repair the short to voltage in circuit DK BLU. Is the repair complete? | -- | System OK | -- |
14 | Use a DVM to measure the voltage between ground and terminal 25 of the EBCM connector. Is the voltage within the specified value? | 0 V | Go to Step 16 | Go to Step 15 |
15 | Repair the short to voltage in circuit YEL. Is the repair complete? | -- | System OK | -- |
16 | Replace the EBCM. Is the repair complete? | -- | System OK | -- |
