Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provide an overview of each diagnostic category. |
DTC Descriptor
DTC P1682: Ignition 1 Switch Circuit 2Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Ignition 1 Voltage (Powertrain Relay) | P0689, P1682, P2176 | P0689, P1516, P1682 | P0689 | -- |
Ignition 1 Voltage (Run/Crank Relay) | -- | P1682 | P0650 | -- |
Circuit/System Description
There are 2 ignition 1 voltage circuits supplied to the engine control module (ECM). The first ignition 1 voltage circuit is provided by the Ignition Relay or the Main Relay, through a fuse. This ignition 1 voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation. The Run/Crank Relay provides the second ignition 1 voltage circuit to the ECM, through a fuse. This ignition 1 voltage provides power to other internal ECM circuits, except those associated with TAC operation. The ECM continuously monitors the voltage level difference between the two circuits.
Conditions for Running the DTC
| • | The ignition is On or the engine is operating. |
| • | The system voltage is more than 5 volts. |
| • | The ignition relay or the main relay is commanded ON. |
| • | DTC P1682 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
The ignition 1 voltage of the Run/Crank relay is more than 3 volts different than the ignition 1 voltage of the main relay for more than 2 seconds.
Action Taken When the DTC Sets
DTC P1682 is a Type B DTC.
Conditions for Clearing the DTC
DTC P1682 is a Type B DTC.
Diagnostic Aids
| • | This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test . |
| • | The engine may operate in a reduced engine power mode. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Engine Control Module Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- Ignition ON, observe the scan tool DTC information parameter. DTC P1682 should not set.
- Ignition ON, observe the scan tool Ignition 1 voltage parameter and the scan tool EC Ignition Relay Feedback parameter. Both readings should be less than 3 volts difference between the two parameters.
- Ignition OFF, observe the scan tool ignition 1 voltage parameter. The reading should be 0 volts, before the ECM powers down.
Circuit/System Testing
- Ignition ON, observe the scan tool Ignition 1 Signal parameter and the scan tool EC Ignition Relay parameter to determine which is less than B+.
- Ignition OFF, remove the relay that corresponds to the scan tool parameter that is less than B+.
- Ignition On, connect a 3A fused jumper wire between B+ and the applicable ignition 1 circuit terminal. Verify the applicable scan tool parameter displays B+.
- If all circuits test normal, test or replace the applicable relay.
Important: 6 ohms or greater in the circuit/underhood fuseblock will cause the DTC to set.
| ⇒ | If the applicable scan tool parameter is less than the specified value, test the ignition 1 circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ECM replacement, setup, and programming |
