For 1990-2009 cars
ABS Components
Wheel Speed Sensors

### Circuit Description

The wheel speed sensor generates an AC signal. The signal is produced when a toothed ring passes the wheel speed sensor. The frequency of the AC signal is proportional to the wheel speed. The EBCM uses the frequency of the signal in order to calculate the wheel speed.

### Conditions for Running the DTC

The ignition is ON.

### Conditions for Setting the DTC

• | The voltage on the high and low circuits is greater than 4.25 volts

| OR

• | The voltage on the high and low circuits is less than 0.75 volts

| OR

• | The voltage on the high circuit is greater than 4.25 volts and the voltage on the low is less than 0.75 volts

Any of the above conditions are present for greater than 0.02 seconds

### Action Taken When the DTC Sets

• | The EBCM disables the ABS

• | The ABS warning indicator turns ON.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.

• | 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

### Diagnostic Aids

The following conditions may cause an intermittent malfunction:

• | A poor connection

• | Rubbed-through wire insulation

• | A broken wire inside the insulation

• | Backed out terminals

• | Improper mating

• | Broken locks

• | Improperly formed or damaged terminals

• | Poor terminal-to-wiring connections

• | Physical damage to the wiring harness

Resistance of the wheel speed sensor will increase with an increase in sensor temperature.

Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems if an intermittent malfunction exists.

### Test Description

The number below refers to the step number on the diagnostic table.

1. This step tests the wheel speed sensor and the wheel speed sensor signal circuits for an open.

2. This step tests the wheel speed sensor and the wheel speed sensor signal circuits for a short to ground.

3. This step tests the wheel speed sensor and the wheel speed sensor signal circuits for a short to voltage.

4. This step tests the wheel speed sensor for the proper resistance value.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 |

1. Turn OFF the ignition.
2. Disconnect the EBCM harness connector.
3. Measure the resistance of the wheel speed sensor circuit.

Does the resistance measure within the specified range?

1000-2000 ohms

Go to Step 3

Go to Step 5

3 | Test the wheel speed sensor circuit for a short to ground. Is a short to ground present? | -- | Go to Step 8 | Go to Step 4
4 | Test the wheel speed sensor circuit for a short to voltage. Is a short to voltage present? | -- | Go to Step 11 | Go to Step 13
5 |

1. Disconnect the wheel speed sensor connector.
2. Measure the resistance across the wheel speed sensor.

Does the resistance measure within the specified range?

1000-2000 ohms

Go to Step 6

Go to Step 15

6 |

1. Disconnect the wheel speed sensor connector.
2. Test the wheel speed sensor signal low circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 7

7 | Test the wheel speed sensor signal high circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
8 |

1. Disconnect the wheel speed sensor connector.
2. Test the wheel speed sensor for an internal short to ground.

Is the wheel speed sensor internally shorted to ground?

--

Go to Step 15

Go to Step 9

9 | Test the wheel speed sensor signal low circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 10
10 | Test the wheel speed sensor signal high circuit for a short to ground. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
11 |

1. Disconnect the wheel speed sensor connector.
2. Turn ON the ignition, with the engine OFF.
3. Test the wheel speed sensor signal low circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 12

12 | Test the wheel speed sensor signal high circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
13 | Inspect for poor connections/terminal tension at the wheel speed sensor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14
14 | Inspect for poor connections/terminal tension at the EBCM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16
15 | Replace the wheel speed sensor. Refer to Rear Wheel Speed Sensor Replacement . Did you complete the repair? | -- | Go to Step 17 | --
16 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the repair? | -- | Go to Step 17 | --
17 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK