P1682
DTC P1682
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptor
DTC P1682
- Ignition 1 Switch Circuit 2
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
There are 2 ignition 1 voltage circuits supplied to the engine control module (ECM). The first ignition 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 second ignition 1 voltage circuit is supplied by the ignition main relay through a fuse, and is used to power the remaining internal ECM circuits. If the ECM detects a voltage difference between the 2 ignition 1 voltage circuits, DTC P1682 will set.
Conditions for Running the DTC
* The ignition is ON.
* System voltage is more than 7 volts.
* The powertrain relay is commanded ON.
* DTC P1682 runs continuously when the above conditions are met.
Conditions for Setting the DTC
The ECM detects that the voltage level difference is greater than 3 volts between the 2 ignition 1 voltage circuits for less than 1 second.
Action Taken When the DTC Sets
DTC P1682 is a Type A code.
Conditions for Clearing the DTC
DTC P1682 is a Type A code.
Diagnostic Aids
This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test (Battery Inspection/Test).
Reference Information
Schematic Reference
Engine Controls Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
J 35616-A/BT-8637 Connector Test Adapter Kit
Circuit/System Verification
Important: On the scan tool, the powertrain relay is referred to as the EC ignition relay.
1. If DTCs P0685, P0689, or P0690 are set, diagnose those DTCs first.
2. Ignition ON, engine OFF, observe both 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.
3. 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
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Ignition OFF, disconnect the powertrain relay.
2. Ignition ON, verify that a test lamp does not illuminate between the powertrain relay controlled output circuit terminal and ground.
• If the test lamp illuminates, test the powertrain relay controlled output circuit for a short to voltage.
3. Ignition OFF, verify that a test lamp illuminates between the powertrain relay coil voltage supply circuit terminal and ground.
• If the test lamp does not illuminate, test the powertrain relay coil voltage supply circuit for a short to ground or an open/high resistance.
4. Verify that a test lamp illuminates between the powertrain relay switch voltage supply circuit terminal and ground.
• If the test lamp does not illuminate, test the powertrain relay switch voltage supply circuit for an open/high resistance.
5. Disconnect the ECM.
6. Ignition ON, verify that a test lamp illuminates between the ECM connector terminal X1-19 and ground.
• If the test lamp does not illuminate, test the ignition 1 relay controlled output circuit for a short to ground or open/high resistance.
• If the circuit tests normal and its fuse is open, replace the ECM.
7. Ignition OFF, connect the harness connector at the ECM.
8. Ignition ON, connect a jumper wire between the powertrain relay voltage supply circuit terminal and the powertrain relay controlled output circuit terminal. Verify the EC Ignition Relay Feedback parameter indicates battery positive voltage.
• If not the specified value, test the powertrain relay controlled output circuit for a short to ground or an open/high resistance. If the circuit tests normal and its fuse is open, replace the ECM.
9. If all circuits test normal, replace the powertrain relay.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Control Module Programming and Setup (Programming and Relearning)
* Engine Control Module Replacement (Service and Repair)
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))