Refer to Data Link Connector Schematics in Electrical Diagnosis
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 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 serial data message from the EBCM, DTC P1602 is set.
Conditions for Running the DTC
| • | The ignition is on. |
| • | The system voltage is greater than 8.2 volts. |
Conditions for Setting the DTC
| • | The PCM detects a loss of serial data from the EBCM. |
| • | The above conditions are present for longer than 5 seconds. |
Action Taken When the DTC Sets
The PCM stores the conditions which were present when the DTC set as Fail Records data only.
Conditions for Clearing the MIL/DTC
| • | A history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | DTC may be cleared by using the scan tool Clear Info function or by disconnecting the PCM battery feed. |
Diagnostic Aids
For complete serial data line schematics, refer to Data Link Connector Schematics in Data Link Communications.
An intermittent may be caused by a faulty connection, rubbed through wire insulation, or a wire broken inside the insulation. Inspect for the following conditions:
| • | An intermittent short circuit on the serial data circuit. Inspect all of the related wiring for an intermittent short to ground or short to voltage. |
| • | Inspect the PCM and the affected control module harness and related connectors for improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connections. |
| • | Inspect the wiring harness for damage. Test for an intermittent short or open circuit in the wiring harnesses related to the affected control module, including the ignition, battery feed, ground, and serial data circuits. Refer to Wiring Repairs in Wiring Systems. |
Reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic System Check? | -- | ||
2 |
Important: If a loss of DLC data has already been diagnosed using the DLC Diagnosis table, clear this DTC and continue diagnosis with the Powertrain On Board Diagnostic (OBD) System Check . Attempt to select ABS Data on the scan tool. Can the ABS data be displayed? | -- | Go to Diagnostic Aids | |
3 |
Was a problem found? | -- | ||
4 |
Was a problem found? | -- | ||
5 |
Was a problem found? | -- | Go to Diagnostic System Check - ABS in Antilock Brake System | |
6 |
Does the scan tool indicate DTC P1602 failed? | -- | System OK |
