For 1990-2009 cars

### Circuit Description

When the electronic brake control relay is activated (turned ON), voltage is supplied to the valve solenoids and pump motor. This DTC identifies a malfunction with the EBCM loosing ground or battery, or when battery is disconnected while running.

### Conditions for Running the DTC

ABS conditions are normal.

### Conditions for Setting the DTC

DTC C1254 is set when a running reset occurs. A running reset occurs when the vehicle is running and functions are normal then suddenly a loss of power or ground connection occurs to the EBCM.

### Action Taken When the DTC Sets

• | ABS is disabled.

• | 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

• | Possible causes for DTC C1254 to set are:

- | Running reset occurred.

- | Loss of EBCM ground.

- | Sudden drop in voltage.

- | Poor or loose grounds connections.

- | Poor or loose power connections.

- | Battery disconnected due to corrosion or loose battery terminals.

- | Internal EBCM malfunction.

• | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step ensures that ignition positive voltage is being received by the EBCM.

2. This step ensures that battery positive voltage is being received by the EBCM.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the ABS Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - ABS
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With the scan tool, observe the Ignition Voltage parameter in the ABS data list.

Does the scan tool indicate that the Ignition Voltage parameter is greater than the specified value?

10.5 V

Go to Step 3

Go to Step 5

3 | With the scan tool, observe the Switched Battery Voltage parameter in the ABS data list. Does the scan tool indicate that the Switched Battery Voltage parameter is greater than the specified value? | 10.5 V | Go to Step 4 | Go to Step 6
4 | Test the charging system. Refer to Symptoms - Engine Electrical in Engine Electrical. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7
5 |

1. Turn OFF the ignition.
2. Disconnect the EBCM connector.
3. Install the J 39700 using the J 39700-99 to the EBCM harness connector only.
4. Test the ignition positive voltage circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

6 |

1. Turn OFF the ignition.
2. Disconnect the EBCM connector.
3. Install the J 39700 using the J 39700-99 to the EBCM harness connector only.
4. Test the battery positive voltage input circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

7 | Test the ground circuit of the EBCM for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8
8 | Inspect for poor connections/terminal tension at the EBCM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9
9 | Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement? | -- | Go to Step 10 | --
10 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK