P0600

Circuit Description
The Powertrain Control Module (PCM) is the control center of the fuel injection system. The PCM constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The PCM also performs the diagnostic function of the system. The PCM can recognize operational problems, alert the driver through the Malfunction Indicator Lamp (MIL) (Check Engine), and store a DTC or DTCs which identify the problem areas to aid the technician in making repairs. The PCM consists of 2 internal sides that communicate to each other. When communication between the 2 sides is lost, the PCM cannot function properly and a DTC will set.

Conditions for Setting the DTC
The PCM cannot communicate between the 2 sides.

Action Taken When the DTC Sets
- The MIL will illuminate.
- The PCM will attempt to record operating conditions at the time this failure is detected, however since this is a internal PCM failure, this information may or may not be reliable. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn "OFF" after three consecutive ignition cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm up cycles without a fault.
- DTCs can be cleared by using a scan tool.

DTC P0600 - Loss of Serial Communication Link:

Test Description
Numbers below refer to the step numbers on the Diagnostic Table.
1. The OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored on the scan tool for later reference.
2. Replacement PCM must be reprogrammed. Refer to the latest Techline information for programming procedures.