P1682

DTC P1682

DTC DESCRIPTOR

DTC P1682
Ignition 1 Switch Circuit 2

DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the prior to using this diagnostic procedure.






CIRCUIT/SYSTEM DESCRIPTION
The Throttle Actuator Control (TAC) System voltage supplies power to the TAC processor independent of the engine control module (ECM) processor. The ECM compares the reported voltage from the TAC processor to the ignition voltage supplied to the ECM processor. If the voltages are not within a specified range of each other the ECM will set this DTC.

CONDITIONS FOR RUNNING THE DTC
- The ignition is in the Unlock/Accessory, Run, or Crank position.
- System voltage is more than 5.23 volts.
- DTC P1682 runs continuously when the above conditions are met.

CONDITIONS FOR SETTING THE DTC
The ignition 1 voltage from the Run/Crank relay is more than 3 volts different from the ignition 1 voltage from the powertrain relay for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- 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 emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

CIRCUIT/SYSTEM VERIFICATION
1. Ensure that the vehicle battery is fully charged and in proper working order.
2. With the ignition ON and the engine OFF, observe the EC Ignition Relay Feedback Signal parameter on the scan tool. The voltage should be more than 10 volts.
- If the voltage is less than 10 volts, continue with Circuit/System Testing.
3. Observe the EC Ignition Relay Feedback Signal parameter on the scan tool while turning OFF the ignition. The voltage should decrease to 0 volts.
- If the voltage is more than 0 volts, continue with Circuit/System Testing.

CIRCUIT/SYSTEM TESTING
1. With the ignition OFF, remove and the ETC fuse from the underhood electrical center and inspect it.
- If the fuse is open, test the Ignition 1 Voltage circuit from the ETC fuse to the ECM for a short to ground or for a faulty ECM.
2. Remove the powertrain relay from the underhood electrical center. Connect a test lamp between the B+ terminal to the switch side of the relay and ground. The test lamp should illuminate.
- If the test lamp does not illuminate, repair the open in the B+ feed circuit to the powertrain relay.
3. Install the powertrain relay.
4. With the ignition ON and the engine OFF, probe each side of fuse block terminals of the ETC fuse, with a test lamp connected to ground. The test lamp should illuminate on one side of the terminals.
- If the test lamp does not illuminate. test the circuit from the powertrain relay to the ETC fuse for an open/high resistance, or for a faulty powertrain relay.
- If the test lamp illuminates on both terminals, test the Ignition 1 Voltage circuit between the ETC fuse and the ECM for a short to voltage or for a faulty ECM.
5. Connect a fused jumper wire to a B+ source.
6. Observe the EC Ignition Relay Feedback Signal parameter on the scan tool. Probe the ECM side of the ETC fuse terminal with the jumper wire. The parameter should be more than 10 volts.
- If the voltage is less than 10 volts, inspect the electrical center for corrosion or spread terminals, test the Ignition 1 Voltage circuit between the ETC fuse and the ECM for an open/high resistance, or for a faulty ECM. All circuit resistance should measure less than 3 ohms.

REPAIR INSTRUCTIONS
- Control Module References for ECM replacement, setup, and programming
- Relay Replacement (Within an Electrical Center) Relay Replacement (Attached to Wire Harness)
- Underhood Electrical Center or Junction Block Replacement

REPAIR VERIFICATION
Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests