DTC C0550. Chevrolet Joy 2008

For 1990-2009 cars

### Circuit Description

The antilock brake system (ABS) control module performs various diagnostic checks on itself. If it finds a problem, it sets DTC C0550.

This procedure checks whether there is a poor ground connection for the electronic brake control module (EBCM).

### DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0550 Electronic Control Unit (ECU) Performance

### Conditions for Running the DTC

• | Vehicle speed is greater than 6 km/h (4 mph) with the brake pedal not applied.

| OR

• | Vehicle speed is greater than 15 km/h (9 mph) and the brake pedal is actuated.

### Conditions for Setting the DTC

• | A connector terminal is corroded.

• | The EBCM is malfunctioning.

### Action Taken When the DTC Sets

The following actions occur:

• | The antilock brake system (ABS) is disabled.

• | The ABS warning indicator turns ON.

• | The electronic brake force distribution (EBD) is disabled.

### 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

It is very important to perform a thorough inspection of the wiring and the connectors. Failure to inspect the wiring and the connectors carefully and completely may result in misdiagnosis, causing part replacement with the reappearance of the malfunction.

### Test Description

The number below refers to the step number on the diagnostic table.

1. This step begins the testing for a poor voltage or ground connection.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: 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 | Use the scan tool to determine if any other DTCs are set. Are other DTCs set? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle | Go to Step 3
2 | Clear all DTCs and road test the vehicle. Does DTC C0550 set again? | -- | Go to Step 5 | Go to Step 4

4

1. Inspect all wiring harness connectors and terminals, especially those at the electronic brake control module (EBCM), for any condition that could cause an intermittent.
2. Repair any problems found.

Did you find and correct the condition?

--

Go to Step 11

--

5

1. Turn the ignition switch to OFF.
2. Disconnect the EBCM connector.
3. Turn the ignition switch to ON.
4. Measure the voltage between ground and terminals 20, 14, and 1 of the EBCM harness connector.

Does the voltage measure within the specified range?

11-14 V

Go to Step 7

Go to Step 6

6 | Inspect the voltage supply and the ground connections to the EBCM for a open or high resistance. Did you find and correct the condition? | -- | Go to Step 11 | --
7 | Inspect the EBCM connector for any ineffective terminals. Are there any ineffective terminals? | -- | Go to Step 8 | Go to Step 9
8 | Repair any connector problem found. Did you complete the repair? | -- | Go to Step 11 | --
9 | Clear all DTCs and road test the vehicle. Does DTC C0550 reset? | -- | Go to Step 10 | System OK
10 | Replace the EBCM. Refer to Brake Pressure Modulator Valve Assembly Replacement . Did you complete the replacement? | -- | Go to Step 11 | --

11

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