For 1990-2009 cars
ABS Components
Cell 44: Wheel Speed Sensors
Handling ESD Sensitive Parts Notice

### Circuit Description

The Electronic Brake Control Module (EBCM) receives right front wheel speed sensor voltage signal through terminal 19 and terminal 20. As a toothed reluctor wheel ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce a small AC voltage signal. This signal's frequency is proportional to the wheel speed.

### Conditions for Setting the DTC

• | DTC C0041 will set when the EBCM detects a sudden change in the right front wheel speed determined to be unreasonable.

• | DTC C0041 can be set anytime.

### Action Taken When the DTC Sets

• | A malfunction DTC stores

• | The ABS disables

• | 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. Although, after the scan tool erases DTC C0041, the EBCM keeps the ABS warning indicator ON until the vehicle is driven 10 mph for at least 20 seconds, AND the right front wheel speed sensor sends a proper signal to the EBCM. Then the EBCM turns OFF the ABS warning indicator. If the right front wheel speed signal is still incorrect, DTC C0041 will set again as a current DTC and the ABS warning indicator remains ON.

### Diagnostic Aids

Inspect for the following when diagnosing this part of the Antilock Brake System (ABS):

• | Loose right front wheel speed sensor

• | Worn right front suspension and/or drivetrain components

• | Right front wheel speed sensor physically damaged

• | Right front wheel speed sensor reluctor wheel toothed ring damaged

Perform a careful visual inspection of the following items:

• | The right front wheel speed sensor reluctor wheel toothed ring

• | The right front CV joint

• | The right front wheel bearing

• | The right front wheel speed sensor

If DTC C0041 sets at the same vehicle speed every time and the right front wheel speed variation is noted above this vehicle speed on the scan tool. The right front wheel speed sensor reluctor wheel toothed ring is most likely damaged. This condition may occur at any vehicle speed.

An intermittent malfunction is most likely caused by a poor connection rubbed thorough wire insulation or a wire that is broken inside the insulation.

If the customer comments reflect that the ABS indicator lamp is ON only during humid conditions (rain, snow, vehicle wash), thoroughly inspect the right front wheel speed sensor circuitry for signs of water intrusion.

Thoroughly inspect any circuitry that is suspected or causing the intermittent complaint for the following conditions:

• | Backed-out terminals

• | Improper mating

• | Broken locks

• | Improperly formed or damaged terminals

• | Poor terminal to wiring connections

• | Physical damage to the wiring harness

| Important: Wheel speed sensor resistance increases with an increase in sensor temperature. When measuring for a short to ground in a wheel speed sensor wiring circuit, manually switch the J 39200 (Digital Multimeter) to the Meg-Ohms range. This will ensure a high resistance short to ground can be found. See J 39200 owners manual.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. Tests for a hardware problem (electrical circuits between the wheel speed sensor and the Electronic Brake Control Module (EBCM). If an open, short to ground or short to voltage is present, circuit repairs must be done first.

2. Excessive tire and or wheel assembly waddle and or play can set this DTC due to excessive wheel speed fluctuations.

3. Tests for a physically damaged wheel speed sensor.

4. Tests for a physically damaged wheel speed sensor reluctor wheel.

5. Tests the internal resistance of the wheel speed sensor for proper values.

6. Tests the voltage output performance of the wheel speed sensor for proper values.

7. Tests for wheel speed sensor circuits shorted together.

8. Tests for poor connections at electrical connectors.

9. Determines whether the condition is intermittent and not due to a malfunctioning EBCM.

10. Performs Electronic Brake Control Module (EBCM) repair confirmation after completed repairs.

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

1. Connect a scan tool to the OBD2 Data Link Connector (DLC).
2. Turn the ignition switch to the ON position.
3. Select Diagnostic Trouble Codes (DTC) on the scan tool.
4. Select DTC Information on the scan tool.
5. Select Current DTC on the scan tool and test for possible Current DTCs.
6. Select History DTC on the scan tool and test for possible History DTCs.

Is DTC C0040 set as a current or history DTC?

--

Go to DTC C0040 RF Wheel Speed Circuit Malfunction

Go to Step 3

3 | Test the right front wheel bearing for excessive play. Refer to Front Suspension for specifications. Is the right front wheel bearing play out of specifications? | -- | Go to Step 11 | Go to Step 4
4 |

1. Turn the ignition switch to the LOCK position.
2. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
3. Remove the right front wheel speed sensor from the steering knuckle by removing one bolt and pulling the wheel speed sensor from the steering knuckle.
4. Inspect the right front wheel speed sensor and its pickup surface area for physical damage.

Does the right front wheel speed sensor have signs of any physical damage?

--

Go to Step 12

Go to Step 5

5 | Inspect the right front wheel speed sensor reluctor wheel for physical damage. Does the right front wheel speed sensor reluctor wheel have signs of physical damage? | -- | Go to Step 13 | Go to Step 6
6 |

1. Disconnect the Electronic Brake Control Module (EBCM) electrical connector.
2. Use J 39200 (DMM) in order to measure the resistance between the EBCM electrical connector terminals 19 and terminal 20 (harness side).

Is the resistance within the specified range?

1120-2520 ohms

Go to Step 7

Go to Step 8

7 |

1. Reinstall the right front wheel speed sensor.
2. Tighten the right front wheel speed sensor bolt to 7.8 N·m (69 lb in).
3. Select the A/C VOLTAGE scale on J 39200 (DMM).
4. Leave J 39200 (DMM) still connected to the EBCM electrical connector terminal 19 and terminal 20 (harness side).
5. Spin the right front wheel by hand while observing voltage reading on J 39200 (DMM).

Is the voltage equal to or greater than the specified voltage?

100 mV

Go to Step 9

Go to Step 12

8 |

1. Remove the right front wheel. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
2. Disconnect the right front wheel speed sensor.
3. Use J 39200 (DMM) in order to measure the resistance between the EBCM electrical connector terminal 19 and terminal 20 (harness side).

Is the resistance equal to the specified value?

OL

(Infinite)

Go to Step 12

Go to Step 14

9 |

1. Inspect the EBCM electrical connector for signs of damage, poor terminal contact, or terminal corrosion that would result in a short or open circuit between the EBCM electrical connector terminal 19 and terminal 20.
2. Inspect the right front wheel speed sensor electrical connector for signs of damage, poor terminal contact, or terminal corrosion.

Did you discover any signs of poor terminal contact, corrosion, or damaged terminals?

--

Go to Step 15

Go to Step 10

10 |

1. Reconnect the EBCM electrical connector.
2. Reconnect the right front wheel speed sensor electrical connector.
3. Disconnect the scan tool from the DLC.
4. Test drive the vehicle at 24 km/h (15 mph) for 30 seconds.
5. Stop the vehicle.
6. Connect a scan tool to the OBD2 Data Link Connector (DLC).
7. Select Diagnostic Trouble Codes (DTC) on the scan tool.
8. Select DTC Information on the scan tool.
9. Select Current DTC on the scan tool.

Does DTC C0041 set as a current DTC?

--

Go to Step 16

Go to Diagnostic System Check - ABS

11 | Repair the excessive right front wheel bearing play. Refer to Front Wheel Hub, Bearing, and Seal Replacement . Is the repair complete? | -- | Go to Step 17 | --
12 | Replace the right front wheel speed sensor. Refer to Front Wheel Speed Sensor Replacement . Is the repair complete? | -- | Go to Step 17 | --
13 | Replace the right front wheel speed sensor reluctor wheel. Refer to Outer Joint and Seal Replacement in Front Wheel Drive Shafts. Is the repair complete? | -- | Go to Step 17 | --
14 | Repair the damaged wiring harness that caused the short between the WHT and BLK wires. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 17 | --
15 | Repair or replace wiring, terminals or connectors that exhibit signs of damage as necessary. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 17 | --
16 | Replace the brake pressure modulator valve assembly. Refer to Brake Pressure Modulator Valve Assembly Replacement . Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
17 |

1. Ensure the EBCM and the right front wheel speed sensor electrical connectors are connected.
2. Turn the ignition switch to the ON position.
3. Select Diagnostic Trouble Codes (DTCs) on the scan tool.
4. Select Clear DTC Information on the scan tool
5. Disconnect the scan tool from the DLC.
6. Test drive Vehicle at 24 km/h (15 mph) for 30 seconds.
7. Stop the vehicle.

Is the ABS warning indicator ON?

--

Go to Diagnostic System Check - ABS

System OK