ABS Light On with DTC C0550 on Medium Duty Models - keywords brakes cold engine hydraulic LG5 light start
| Subject: | ABS Light on With DTC C0550 on Medium Duty Models |
| Models: | 2005 Chevrolet Kodiak C6500 C7500 |
| 2005 GMC TopKick C6500 C7500 |
| With CAT Diesel Engine (RPO LG5) and Hydraulic Brakes |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
2005 Chevrolet and GMC C65/C75 models with a CAT LG5 Diesel Engine and hydraulic brakes may illuminate the ABS light and set a DTC C0550 for low voltage after a cold start when the CAT air intake heater is activated.
The CAT air intake heater along with other active accessories may produce enough electrical current draw after a cold start to cause the ABS module to register a low voltage signal and set a DTC C0550.
Recommendation/Instructions:
A new pigtail jumper harness that incorporates a diode is now available from GM SPO under P/N 94666008. The new jumper harness will plug into the CAT air intake heater relay connector and will prevent a low voltage signal in the ABS module after cold starts.
The CAT air intake heater relay is located at the front left side of the engine as shown on SI Document ID # 690878. The air intake heater relay connector wiring diagram is shown on SI Document ID # 1492198.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
