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) | -- | ¹ | P0575, P0650 | -- |
¹The condition causes no start condition. | ||||
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, Engine OFF. Powertrain relay is commanded ON | |||
Ignition 1 Voltage | 0 V | 0 V | 12 V |
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, Engine OFF. Run/Crank Relay commanded ON | |||
Ignition 1 Voltage | 0 V | 0 V | 12 V |
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. 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. The ignition 1 voltage provides power to other internal ECM circuits, except those associated with TAC operation. The ECM continuously monitors the voltage difference between the 2 circuits.
Conditions for Running the DTC
| • | The ignition switch is in Unlock/Accessory, Run or Crank. |
| • | System voltage is greater than 5.23 volts. |
| • | Powertrain relay is commanded ON. |
| • | DTC P1682 runs continuously when the above conditions are met. |
Conditions for Setting the DTC
| • | The difference between the ignition 1 voltage of the Run/Crank relay and the ignition 1 voltage of the powertrain is more than 3 volts. |
| • | It occurs every time in 14 times tests. |
Action Taken When the DTC Sets
| • | DTC P1682 is a Type A DTC. |
| • | The 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.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Engine Control Module Description
Electrical Information Reference
DTC Type Reference
Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Circuit/System Verification
- If DTC P0685, P0690, or P1380 are set, diagnose those DTCs first.
- With the engine OFF, turn the ignition ON, observe the Ignition 1 signal, and the EC Ignition Relay Feedback Signal parameters on the scan tool. 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 volt, before the ECM powers down.
Circuit/System Testing
- Ignition ON, observe the Ignition 1 Signal and EC Ignition Relay Feedback Signal parameters on the scan tool to determine which is less than B+.
- Ignition OFF, remove the relay that corresponds to the scan tool parameter that is less than battery positive.
- Ignition On, connect a 3-amp fused jumper wire between battery positive voltage and the appropriate ignition 1 circuit terminal.
- If all circuits test normal, test or replace the applicable relay.
Note: Six ohms or greater in the circuit/underhood fuse block will cause the DTC to set.
| ⇒ | If the appropriate scan tool parameter is less than the specified value, test the ignition 1 circuit for an open/high resistance. If the circuit test normal, replace the ECM. If the circuit test 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
