Refer to
.
Circuit Description
The powertrain control module (PCM) uses the Class 2 Serial Data circuit to communicate with various other devices and systems in the vehicle. The PCM ensures that communication remains established by monitoring the Class 2 Serial Data circuit for state of health messages from the other devices using the circuit. If the PCM detects a loss of the state of health messages from the instrument panel cluster (IPC), DTC P1604 will be set.
Conditions for Running the DTC
| • | The ignition is ON. |
| • | The system voltage is more than 8.2 volts. |
Conditions for Setting the DTC
| • | The PCM detects a loss of serial data from the IPC. |
| • | The above condition is present for more than 5 seconds. |
Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.
Conditions for Clearing the MIL/DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Diagnostic Aids
Inspect for the following conditions:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Important: : If a loss of the data link connector (DLC) data has already been diagnosed, clear this DTC and continue the diagnosis with Powertrain On Board Diagnostic (OBD) System Check . Are any UXXXX DTCs present? | -- | Go to Diagnostic Trouble Code (DTC) List in Data Link Communications | |
3 |
Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | -- | |
4 |
Does the scan tool indicate this DTC failed? | -- | System OK |
