For 1990-2009 cars
ABS Components
Antilock Brake System Schematics
Handling ESD Sensitive Parts Notice

### Circuit Description

Ignition voltage is supplied to terminal 86 of the Electronic Brake Control Relay. The above enables the EBCM to energize the pullin coil by completing the ground circuit at connector terminal A11 of the EBCM. The magnetic field created closes the Electronic Brake Control Relay contacts. The magnetic field also allows battery voltage and current through the Electronic Brake Control Relay terminal 30 to be supplied to the EBCM through connector terminal C. Connector terminal C supplies power to the EBCM, which supplies power to the motors and solenoids.

### Conditions for Setting the DTC

• | DTC C1218 can set after the EBCM commands the Electronic Brake Control Relay ON.

• | This test monitors the availability of voltage to the EBCM.

• | DTC C1286 is set with DTC C1218 if the rear channel is not expected to be in the home position.

### 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.

• | 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.

### Diagnostic Aids

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.

Clear the DTCs after completing the diagnosis. Test drive the vehicle for three drive cycles in order to verify that the DTC does not reset. Use the following procedure in order to complete one drive cycle:

1. Start the vehicle.
2. Drive the vehicle over 16 km/h (10 mph).
3. Stop the vehicle.
4. Turn the ignition to the OFF position.

### Test Description

1. This test determines if the EBCM is capable of controlling the electronic brake control relay as commanded.

2. This test checks for a short to voltage in the switched battery input circuit between the electronic brake control relay and the EBCM.

3. This test checks for an open or high resistance in the electronic brake control relay pull-in coil.

4. This test checks for electronic brake control relay contacts stuck in the closed position.

5. This test determines if the malfunction is caused by the EBCM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
Important: Zero the J 39200 test leads before making any resistance measurements. Refer to the J 39200 user's manual.
1 | Was the ABS Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 |

1. Turn the ignition switch to the OFF position.
2. Install a Scan Tool .
3. Turn the ignition switch to the RUN position.

Do not start the engine.

4. Use the Relay Test function under Special Functions of the Scan Tool in order to command the Electronic Brake Control Relay ON.

Does the Scan Tool indicate that the Electronic Brake Control Relay is ON, and is the voltage equal to or greater than the specified voltage?

10 V

Go to Step 12

Go to Step 3

3 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the Electronic Brake Control Relay.
3. Disconnect the EBCM connector.
4. Turn the ignition switch to the RUN position.

Do not start the engine.

5. Use the J 39200 in order to measure the voltage between the EBCM harness connector terminal A11 and ground.

Is the voltage within the specified voltage?

0-2 V

Go to Step 4

Go to Step 9

4 |

1. Turn the ignition switch to the OFF position.
2. Use the J 39200 in order to measure the resistance between the Electronic Brake Control Relay terminal 85 and the Electronic Brake Control Relay terminal 86.

Is the resistance equal to or greater than the specified range?

65-95 ohms

Go to Step 5

Go to Step 10

5 | Use the J 39200 in order to measure the resistance between the Electronic Brake Control Relay terminal 30 and the Electronic Brake Control Relay terminal 87. Is the resistance within the specified range? | OL (Infinite) | Go to Step 6 | Go to Step 10
6 |

1. Inspect the following components:

• | The EBCM connector terminal A11

• | The remaining terminals of the EBCM connector

2. Inspect the above components for the following conditions:

• | Damage

• | Poor terminal contact

• | Terminal corrosion

Are there signs of poor terminal contact, corrosion, or damaged terminals?

--

Go to Step 8

Go to Step 7

7 |

1. Reconnect the EBCM connector.
2. Reconnect the Electronic Brake Control Relay.
3. Turn the ignition switch to the RUN position.

Do not start the engine.

4. Use the Scan Tool in order to look for DTCs.

Does DTC C1218 set as a current DTC?

--

Go to Step 11

Go to Step 12

8 | Replace all of the terminals or connectors that exhibit signs of poor terminal contact, corrosion, or damaged terminal(s). Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
9 | Repair the short to voltage in the BLK/BLU wire between the relay box and the EBCM. Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
10 | Replace the Electronic Brake Control Relay. Refer to Electronic Brake Control Relay Replacement . Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
11 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check - ABS | --
12 | The malfunction is intermittent or is not present at this time. Refer to Diagnostic Aids for more information. Is the action complete? | -- | System OK | --