For 1990-2009 cars
ABS Components
Antilock Brake System Schematics

### Circuit Description

The EBCM uses the Powertrain Control Module (PCM) to increase the engine idle speed during certain ABS events, especially those on icy road conditions. The EBCM is connected to the PCM through CKT 9Y01. When deemed necessary, the EBCM grounds this circuit which signals the PCM to increase idle speed from 850 rpm to 1500-2000 rpm. If an open or short to battery occurs in CKT 9Y01, the EBCM will be unable to request the PCM to increase engine speed.

If a short to ground occurs in CKT 9Y01, the PCM will increase the engine idle speed continuously, once the vehicle speed has reached at least 20 km/h (12 mph).

### Conditions for Setting the DTC

This DTC will set when the following conditions are met:

• | This DTC can be set anytime after initialization for an open or short to ground in CKT 9Y01.

• | The EBCM can detect a short to voltage in CKT 9Y01 only during the time that the EBCM is requesting the PCM to idle-up.

### Action Taken When the DTC Sets

• | A malfunction DTC stores.

• | The ABS remains functional.

### 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.

Any circuitry that is suspected of causing the intermittent complaint should be thoroughly checked for improper mating, improperly formed or damaged terminals, poor terminal to wiring connections, or physical damage to the wiring harness.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Was the Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check
2 |

1. Turn the ignition switch to LOCK.
2. Disconnect EBCM connector C1.
3. Disconnect the PCM connector C1.
4. Using J 39200 measure resistance between EBCM harness connector C1 terminal C15 and ground.

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

OL

(Infinite)

Go to Step 3

Go to Step 7

3 |

1. Turn the ignition switch to ON.
2. Using J 39200 measure voltage between EBCM harness connector C1 terminal C15 and ground.

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

0-1 V

Go to Step 4

Go to Step 8

4 | Using J 39200 measure resistance between EBCM harness connector C1 terminal C15 and PCM harness connector C1 terminal 20 (terminal 17 on vehicles equipped with 4-speed A/T). Is the resistance within the range specified in the Value(s) column? | 0-2 ohms | Go to Step 5 | Go to Step 9
5 |

1. Turn ignition switch to LOCK.
2. Reconnect EBCM connector C1.
3. Reconnect PCM connector C1.
4. Raise and suitably support vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Make sure driving wheels are off the ground as they will rotate during the test.
5. Install Scan Tool and select idle-up test.
6. Start and warm up engine to normal operating temperature (this test will not work if the engine is cold).
7. Accelerate driving wheels to 25 km/h (15 mph) and maintain speed.
8. Release accelerator, let engine return to idle speed (while transmission is still in gear), then quickly command ON the idle-up circuit with the Scan Tool .

Note: If the speed of the driving wheels drop below 25 km/h (15 mph) while commanding ON the idle-up circuit, the PCM will ignore and requests to idle-up from the EBCM. This is a normal condition. Repeat step 7 above if needed.

9. Press brake pedal to stop driving wheels, and turn the engine off.

Notice if the engine rpm increases from idle speed to 1500-2000 rpm when the idle-up circuit is commanded ON during this test. Does the engine speed increase as described?

--

Go to Step 10

Go to Step 6

6 |

1. Connect J 39200 Between ground and EBCM harness connector C1 terminal C15 by backprobing.
2. Turn ignition switch to ON.
3. Command ON the idle-up circuit with Scan Tool while measuring voltage on J 39200 .

Is the voltage measured within the range specified in the Value(s) column when idle-up circuit is commanded ON?

0-1 V

Go to Step 11

Go to Step 12

7 | Repair the short to ground in CKT 9Y01. Is the repair complete? | -- | Go to Diagnostic System Check | --
8 | Repair the short to voltage in CKT 9Y01. Is the repair complete? | -- | Go to Diagnostic System Check | --
9 | Repair the open in CKT 9Y01. Is the repair complete? | -- | Go to Diagnostic System Check | --
10 | Malfunction not present at this time. Refer to Diagnostic Aids for additional information regarding this DTC. Is the action complete? | -- | Go to Diagnostic System Check | --
11 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls. Is the repair complete? | -- | Go to Diagnostic System Check | --
12 | Inspect EBCM connector C1 for poor terminal contact, open or high resistance in CKT 9Y01. If wiring is OK, replace the EBCM. Refer to Electronic Brake Control Module Replacement . Is the repair complete? | -- | Go to Diagnostic System Check | --