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 provides 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, P1516, P1682 | P0689, P1516, P1682, P2101 | P0690 | -- |
Ignition 1 Voltage (Run/Crank Relay) | -- | P0689, P1516, P1682 | P0575, P0650 | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON Engine OFF. Powertrain Relay commanded ON. | |||
Ignition 1 voltage | 0 volts | 0 volts | 12 volts |
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON Engine OFF. Run/Crank Relay commanded ON. | |||
Ignition 1 voltage | 0 volts | 0 volts | 12 volts |
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 powertrain 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 2 circuits.
Conditions for Running the DTC
| • | The ignition is in the Unlock/Accessory, Run, or Crank position. |
| • | System voltage is more than 5.23 volts. |
| • | The powertrain relay is commanded ON. |
| • | DTC P1682 runs continuously when 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 powertrain relay for more than 1 second.
Action Taken When the DTC Sets
| • | DTC P1682 is a Type A DTC. |
| • | Engine may operate in a reduced engine power mode. |
Conditions for Clearing the DTC
DTC P1682 is a Type A 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 .
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
- If DTCs P0685, P0689, or P0690 are set, diagnose those DTCs first.
- Ignition ON, engine OFF, observe the Ignition 1 voltage signal, and the EC Ignition Relay Feedback signal parameters, on the scan tool. Both parameter values should display no more than 3 volts difference, between the 2 parameters.
- Ignition OFF, observe the ignition 1 voltage signal parameter, on the scan tool. The parameter value should be 0 volts, before the ECM powers down.
- Engine running, observe the DTC information with a scan tool. DTC P1682 should not set.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition ON, observe the Ignition 1 Signal and EC Ignition Relay Feedback scan tool parameters 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 that the applicable scan tool parameter displays B+.
- If all circuits test normal, test or replace the applicable relay.
Important: Six ohms or greater in the circuit/underhood fuse block 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
