P1602

Engine Controls Schematics: MIL And Data Link Connector:

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) uses the 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 (SOH) messages from the other devices using the circuit. If the PCM detects a loss of the SOH serial data message from the EBTCM, DTC P1602 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 EBTCM.
^ The above conditions are present for more than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data.

Diagnostic Chart:

CONDITIONS FOR CLEARING THE MIL/DTC
^ A History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.

DIAGNOSTIC AIDS
An intermittent may be caused by a faulty connection, rubbed through wire insulation, or a wire broken inside the insulation. Check for the following conditions:
^ An intermittent short circuit on the serial data circuit-Refer to 310 Serial Data Class 2 and check all related wiring for an intermittent short to ground or a 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. Check 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 Testing for Intermittent and Poor Connections in Diagrams.

Reviewing the Failure 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.