Circuit Description
The Electronic Brake Control Module (EBCM) receives the voltage signal from the right front wheel speed sensor through terminals 19 and 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 unreasonable change in the right front wheel speed. |
| • | 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 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):
| • | A loose right front wheel speed sensor. |
| • | Worn right front suspension and/or drivetrain components. |
| • | The right front wheel speed sensor is physically damaged. |
| • | The toothed ring on the reluctor wheel from the right front wheel speed sensor is damaged. |
Visually inspect the following items:
| • | The toothed ring on the reluctor wheel from the right front wheel speed sensor |
| • | The right front CV joint |
| • | The right front wheel bearing |
| • | The right front wheel speed sensor |
An intermittent malfunction is probably caused by a poor connection rubbed thorough wire insulation, or by a wire that is broken inside the insulation.
If 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.
Inspect the harness connectors 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 |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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The Diagnostic System Check must be the starting point for any ABS related diagnosis.
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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.
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Excessive tire and or wheel assembly waddle and or play can set this DTC due to excessive wheel speed fluctuations.
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Tests for a physically damaged wheel speed sensor.
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Tests for a physically damaged wheel speed sensor reluctor wheel.
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Tests the internal resistance of the wheel speed sensor for proper values.
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Tests the voltage output performance of the wheel speed sensor for proper values.
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Tests for wheel speed sensor circuits shorted together.
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Tests for poor connections at electrical connectors.
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Determines whether the condition is intermittent and not due to a malfunctioning EBCM.
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Performs Electronic Brake Control Module (EBCM) repair confirmation after completed repairs.
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 to 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.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Diagnostic System Check | |
2 |
Is DTC C0040 set as a current or history DTC? | -- | ||
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? | -- | ||
4 |
Does the right front wheel speed sensor have signs of any physical damage? | -- | ||
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? | -- | ||
6 |
Is the resistance within the range specified in the Value(s) column? | 1120-2520 ohms | ||
7 |
Is the voltage equal to or greater than the voltage specified in the Value(s) column? | 100 mV | ||
8 |
Is the resistance equal to the value specified in the Value(s) column? | OL Infinite | ||
9 |
Did you find any signs of poor terminal contact, corrosion, or damaged terminals? | -- | ||
10 |
Does DTC C0041 set as a current DTC? | -- | Go to Diagnostic System Check | |
11 | Repair the excessive right front wheel bearing play. Refer to Front Wheel Hub, Bearing, and Seal Replacement for service procedure. Is the repair complete? | -- | -- | |
12 | Replace the right front wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Is the repair complete? | -- | -- | |
13 | Replace the right front wheel speed sensor reluctor wheel. Refer to Outer Joint and Seal Replacement . Is the repair complete? | -- | -- | |
14 | Repair the damaged wiring harness that caused the short between CKT 833 and CKT 872. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
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? | -- | -- | |
16 | Replace the brake pressure modulator valve assembly. Refer to Brake Pressure Modulator Valve Assembly Replacement . Is action complete? | -- | Go to Diagnostic System Check | -- |
Is the ABS indicator ON? | -- | Go to Diagnostic System Check | -- |
