Antilock Brake System (ABS) Lamp Illuminated, Diagnostic Trouble Code (DTC) C0550 Set (Install Jumper Harness)
| Subject: | Antilock Brake System (ABS) Lamp Illuminated, Diagnostic Trouble Code (DTC) C0550 Set (Install Jumper Harness) |
| Models: | 2003-2006 Chevrolet Kodiak C6500-C8500 Series |
| 2003-2006 GMC TopKick C6500-C8500 Series |
| with 7.2L CAT Engine (VIN C -- RPO LG5) and Hydraulic ABS Brakes |
Condition
Some customers/dealers may comment that the ABS lamp is illuminated on start-up. Upon further investigation, the technician may find DTC C0550 set. This condition affects vehicles operated primarily in cold climates.
Cause
The CAT engine air inlet heater relay cycles on and off during a cold start. When the relay cycles, a voltage spike may travel through the system, resulting in voltage fluctuation in the ABS controller. The controller recognizes the fluctuation and sets the C0550 code.
Correction
Install a jumper harness with a diode, P/N 94666008, inline in the wire harness connector to the CAT air intake heater relay as shown above. The CAT intake air heater relay is located at the front left side of the engine. Refer to the Intake Air (IA) Heater schematic in Document ID# 1492198.
The new harness will have a barcode label around the harness as shown above. If the harness in the suspect vehicle has this barcode, then the vehicle has the new harness installed. If the vehicle has this condition and has had the new harness installed, another condition may be contributing to this. Refer to the applicable diagnostic information in SI.
Parts Information
Part Number | Description |
|---|---|
94666008 | Harness Asm-Eng Wrg Harn Ext. |
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
N2829 | Relay - Engine Wiring - Replace | Use published labor operation time |
