P0689
DTC P0689
CIRCUIT DESCRIPTION
The powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit, called an output driver module. When the ECM commands the relay ON, ignition 1 voltage is supplied to the ECM through the V8 ECM fuse in the underhood fuse block. This ignition 1 voltage input to the ECM provides the ignition power for the ECM circuitry and is also used to confirm the relay contacts have closed. A voltage less than 10 volts indicates an open, high resistance, or a short to ground in the ignition 1 voltage circuit to the ECM. This DTC will set when the ECM detects less than 10 volts on the ignition 1 voltage circuit to the ECM, after the ignition switch is turned ON.
DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0689 Computers and Control Systems Ignition Relay Feedback Circuit Low Voltage
CONDITIONS FOR RUNNING THE DTC
- The battery voltage is more than 11 volts for 1.5 seconds with the ignition ON.
- DTC P0689 runs continuously when the above condition is met.
CONDITIONS FOR SETTING THE DTC
The ECM detects less than 10 volts on the ignition 1 voltage circuit for more than 200 milliseconds.
ACTION TAKEN WHEN THE DTC SETS
- The control module stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center, if equipped, may display a message.
CONDITIONS FOR CLEARING THE DTC
- A current DTC Last Test Failed clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- Clear the DTC with a scan tool.
DIAGNOSTIC AIDS
- The powertrain relay will remain powered up for 15 seconds after the ignition switch is turned OFF.
- This diagnostic table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test. Battery Inspection/Test
TEST
