For 1990-2009 cars

### Circuit Description

The electronic brake control module (EBCM) sends antilock brake system (ABS) data to the engine control module (ECM). The data is sent to the ECM through a communication network called the GM local area network (LAN). Two circuits are used to communicate LAN data between the ECM and EBCM. A fault in the LAN will not cause DTC U0415 to set by itself. If a LAN fault occurs, other DTCs will set in addition to DTC U0415.

If the ECM receives invalid antilock brake system data from the EBCM, this DTC sets.

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC U0415 EBCM Communication Circuit Performance

### Conditions for Running the DTC

• | The ignition is on for more than 3 seconds.

• | The ignition 1 voltage is between 10.5-18 volts.

• | No other communication errors are present.

• | DTC U0415 runs continuously once the above conditions are met.

### Conditions for Setting the DTC

The ECM receives no valid antilock brake system data from the EBCM for more than 1 second.

### Action Taken When the DTC Sets

• | When the diagnosis is running and fails, the control module stores the DTC information in memory.

• | Malfunction indicator lamp (MIL) will not illuminate.

• | The control module records run status when diagnosis does not pass. The control module stores this information in Failure Records.

• | The DIC, if equipped, will display a piece of information.

### Conditions for Clearing the DTC

• | When the diagnosis is running and passes, the current DTC (DTC previously tested and failed) is cleared.

• | If this diagnosis or other diagnosis which is not related to emission is reported without failure, it will clear history DTC after 40 continuous warm-up cycles.

• | Clear the DTCs with the scan tool.

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Engine Controls Schematics Connector End View Reference: Component Connector End Views or Antilock Brake System Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn ON the ignition, with the engine OFF.

Note: Record all Failure Records before clearing the DTC. Using Clear Info erases the Failure Records from the engine control module (ECM).

2. Record the DTC Freeze Frame/Failure Records.

Did you record any Freeze Frame/Failure Records for a DTC other than U0415?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3 |

1. Clear the DTC Information with a scan tool.
2. Turn the ignition OFF for at least 30 seconds.
3. Start, and allow the engine to idle.

Did DTC U0415 fail this ignition?

Go to Step 4

Go to Intermittent Conditions

4 | Did any electronic brake control module (EBCM) DTCs or any other "U" DTC also set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 5
5 | Test the LAN circuits in the wiring harness between EBCM and the ECM for a high resistance or a poor connection at the module connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 7 | Go to Step 6
6 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 7 | --
7 |

1. Clear the DTCs with a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 8

8 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle | System OK