For 1990-2009 cars
ABS Components
Antilock Brake System Schematics

### Circuit Description

The Electronic Brake Control Module (EBCM) receives a voltage signal from the left rear wheel speed sensor through terminals 8 and 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, unreasonable change in the left rear wheel speed.

• | 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 conditions when diagnosing this part of the Antilock Brake System (ABS):

• | Loose left rear wheel speed sensor.

• | A worn left rear suspension and/or drivetrain components.

• | The left rear wheel speed sensor is physically damaged.

• | The toothed ring of the reluctor wheel from the left rear wheel speed sensor is damaged.

Visually inspect the following items:

• | The toothed ring of the reluctor wheel from the left rear wheel speed sensor

• | The left rear wheel bearing

• | The left rear wheel speed sensor

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

If 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.

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.

1. The Diagnostic System Check must be the starting point for any ABS related diagnosis.

2. 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.

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

4. Tests for a physically damaged wheel speed sensor.

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

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

7. Tests the voltage output performance of the wheel speed sensor.

8. Tests for wheel speed sensor circuits shorted together.

9. Tests for poor connections at electrical connectors.

10. Determines whether the condition is intermittent and not due to a faulty EBCM.

11. 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 Step 2 | Go to Diagnostic System Check
2 |

1. Connect a scan tool to the 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 C0045 set as current or history DTC?

--

Go to DTC C0045 LR Wheel Speed Circuit Malfunction

Go to Step 3

3 | Test 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
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 left rear wheel speed sensor.
4. Inspect the left rear wheel speed sensor and its pickup surface area for physical damage.

Does the left rear wheel speed sensor have signs of any physical damage?

--

Go to Step 12

Go to Step 5

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
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 terminal 8 and terminal 4 (harness side).

Is the resistance within the range specified in the Value(s) column?

1120-2520 ohms

Go to Step 7

Go to Step 8

7 |

1. Reinstall the left rear wheel speed sensor.
2. Tighten the left rear 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 connected to the EBCM electrical connector terminal 8 and terminal 14 (harness side).
5. Spin the left rear wheel by hand while observing voltage reading on J 39200 DMM.

Is the voltage equal to or greater than the voltage specified in the Value(s) column?

100 mV

Go to Step 9

Go to Step 12

8 |

1. Remove the rear seatback. Refer to Rear Seat Back Replacement in Seats.
2. Disconnect the left rear wheel speed sensor connector.
3. Use J 39200 DMM in order to measure the resistance between the EBCM electrical connector terminal 8 and terminal 14 (harness side).

Is the resistance equal to the value specified in the Value(s) column?

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 between the EBCM electrical connector terminal 8 and terminal 14.
2. Inspect the left rear wheel speed sensor electrical connector for signs of damage, poor terminal contact, or terminal corrosion.

Did you find 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 left rear 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 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 C0046 set as a current DTC?

--

Go to Step 16

Go to Diagnostic System Check

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 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 CKT 884 and CKT 885. 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 | --
17 |

1. Connect the EBCM electrical connector and the left rear wheel speed sensor electrical connector.
2. Disconnect the scan tool from the DLC.
3. Test drive Vehicle at 24 km/h (15 mph) for 30 seconds.
4. Stop the vehicle.

Is the ABS indicator ON?

--

Go to Diagnostic System Check

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