For 1990-2009 cars
ABS Components
Antilock Brake System Schematics

### Circuit Description

The Electronic Brake Control Module (EBCM) monitors available voltage level at terminal B (CKT 642).

### Conditions for Setting the DTC

This DTC will set if the voltage level at terminal 13 or terminal B is less than 8 volts.

### 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.

### Diagnostic Aids

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

• | Vehicle charging system is not operating properly (low generator output or faulty battery).

• | High resistance in the ignition power circuit (CKT 641) or the solenoid power input circuit (CKT 642).

• | Poor G103.

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

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

### 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 for proper generator output.

3. Tests for high resistance in the solenoid power input circuit (CKT 642).

4. Tests for high resistance in the ground circuit (CKT 1050).

5. Tests for high resistance in the ignition power input circuit (CKT 641).

6. Determines whether the condition is present during an ABS stop.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check
2 | Test the vehicle charging system. Refer to Charging System Check in Engine Electrical. Is the vehicle charging system output below specifications? | -- | Go to Step 7 | Go to Step 3
3 |

1. Turn the ignition switch to the LOCK position.
2. Disconnect the Electronic Brake Control Module (EBCM) electrical connector.
3. Disconnect the negative battery terminal cable.
4. Disconnect the positive battery terminal cable.
5. Use J 39200 DMM in order to measure the resistance between the EBCM electrical connector terminal B (harness side) and the positive battery cable.

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

0-2 ohms

Go to Step 4

Go to Step 8

4 | Use J 39200 DMM in order to measure the resistance between the EBCM electrical connector terminal A (harness side) and ground. Is the vehicle charging system output below specifications? | 0-2 ohms | Go to Step 5 | Go to Step 12
5 |

1. Turn the ignition switch to ON position (this action completes the circuit to be tested).
2. Use J 39200 DMM in order to measure the resistance between the Electronic Brake Control Module (EBCM) electrical connector terminal 13 (harness side) and the positive battery cable.

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

0-2 ohms

Go to Step 6

Go to Step 9

6 |

1. Reconnect the EBCM electrical connector.
2. Reconnect the positive battery terminal cable.
3. Reconnect the negative battery terminal cable.
4. Connect a scan tool to the Data Link Connector (DLC).
5. Turn the ignition switch to the ON position.
6. Select Diagnostic Trouble Codes (DTC) on the scan tool.
7. Select Clear DTC Information on the scan tool.
8. Test drive the vehicle at 24 km/h (15 mph) for 30 seconds.
9. When driving conditions permit, perform an ABS stop bringing the vehicle to a complete stop.
10. Park the vehicle and engage the parking brake.
11. Select Diagnostic Trouble Codes (DTC) on the scan tool.
12. Select DTC Information on the scan tool.
13. Select Current DTC on the scan tool.

Is DTC C0899 set as a Current DTC?

--

Go to Step 10

Go to Step 11

7 | Repair the vehicle's charging system. Refer to Charging System Check in Engine Electrical. Is action complete? | -- | Go to Diagnostic System Check | --
8 | Repair the open or high resistance in CKT 642. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | --
9 | Repair the open or high resistance in CKT 641. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | --
10 |

1. Test CKT 641 and CKT 642 for high resistance. Test for tight clean EBCM grounds.
2. Inspect the EBCM electrical connector and its in-harness connectors fuse and relay box terminals for signs of high resistance or poor terminal contact.
3. If wiring and connector terminals are OK, replace the brake pressure modulator valve assembly. Refer to Brake Pressure Modulator Valve Assembly Replacement .

Is the repair complete?

--

Go to Diagnostic System Check

--

11 | A malfunction is not present at this time. Refer to Diagnostic Aids for additional information regarding this DTC. Is the action complete? | -- | Go to Diagnostic System Check | --
12 | Repair the open or high resistance in CKT 1050. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Diagnostic System Check | --