Circuit Description
The Electronic Brake Control Module (EBCM) receives left rear wheel speed sensor voltage signal through terminal 8 and terminal 14. 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 C0046 will set when the EBCM detects a sudden change in the left rear wheel speed determined to be unreasonable. |
| • | DTC C0046 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. If the left rear wheel speed signal is still incorrect DTC C0046 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 left rear wheel speed sensor |
| • | Worn left rear suspension and/or drivetrain components |
| • | Left rear wheel speed sensor physically damaged |
| • | Left rear wheel speed sensor reluctor wheel toothed ring damaged |
Perform a careful visual inspection of the following items:
| • | The left rear wheel speed sensor reluctor wheel toothed ring |
| • | The left rear wheel bearing |
| • | The left rear wheel speed sensor |
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 warning indicator is ON only during humid conditions (rain, snow, vehicle wash), thoroughly inspect the left rear 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.
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Tests 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.
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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.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | |
Is DTC C0045 set as current or history DTC? | -- | Go to Step 3 | ||
Check the left rear wheel bearing for excessive play. Refer to Rear Suspension for specifications. Is the left rear wheel bearing play out of specifications? | -- | Go to Step 11 | Go to Step 4 | |
Does the left rear wheel speed sensor have signs of any physical damage? | -- | Go to Step 12 | Go to Step 5 | |
Inspect the left rear wheel speed sensor reluctor wheel for physical damage. Does the left rear wheel speed sensor reluctor wheel have signs of physical damage? | -- | Go to Step 13 | Go to Step 6 | |
Is the resistance within the specified range? | 1120-2520 ohms | Go to Step 7 | Go to Step 8 | |
Is the voltage equal to or greater than the specified voltage? | 100 mV | Go to Step 9 | Go to Step 12 | |
Is the resistance equal to the specified value? | OL (Infinite) | Go to Step 12 | Go to Step 14 | |
Did you observe any signs of poor terminal contact corrosion or damaged terminals? | -- | Go to Step 15 | Go to Step 10 | |
Does DTC C0046 set as a current DTC? | -- | Go to Step 16 | ||
11 | Repair the excessive left rear wheel bearing play. Refer to Rear Wheel Bearing and Hub Replacement in Rear Suspension. Is the repair complete? | -- | Go to Step 17 | -- |
12 | Replace the left rear wheel speed sensor. Refer to Rear Wheel Speed Sensor Replacement . Is the repair complete? | -- | Go to Step 17 | -- |
13 | Replace the left rear wheel hub. Refer to Rear Wheel Bearing and Hub Replacement in Rear Suspension. Is the repair complete? | -- | Go to Step 17 | -- |
14 | Repair the damaged wiring harness that caused the short between the PNK and PPL 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? | -- | -- | |
Is the ABS warning indicator ON? | -- | -- |
