P1682
DTC P1682
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions 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 voltage circuits supplied to the engine control module (ECM). The first ignition circuit is provided by the powertrain relay, through a fuse. This ignition voltage circuit supplies power to all the internal ECM circuits associated with the throttle actuator control (TAC) operation. The second ignition voltage circuit is supplied by the ignition 1 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 voltage circuits, DTC P1682 will set.
Conditions for Running the DTC
* The ignition is ON.
* System voltage is more than 7 V.
* 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 V between the 2 ignition 1 voltage circuits for less than 1 s.
Action Taken When the DTC Sets
DTC P1682 is a Type A DTC.
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 Battery Inspection/Test.
Reference Information
Schematic Reference
* Engine Controls Schematics [1][2]Electrical Diagrams
* Power Distribution Schematics Power Distribution Schematics
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Electrical Center Identification Views Fuse Block - Underhood Label (North America)
* Probing Electrical Connectors Probing Electrical Connectors
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
J 35616-A/BT-8637 - Connector Test Adapter Kit
Circuit/System Verification
Note: 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. There should be no more than 3 V 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
Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Ignition ON, observe the Ignition 1 Signal and the EC Ignition Relay Feedback scan tool parameter to determine which is more than 3 V lower than the other.
Note: The Ignition 1 Signal is supplied by the Ignition 1 relay. The EC Ignition Relay Feedback signal is supplied by the powertrain relay.
2. Ignition OFF, remove the relay that corresponds to the scan tool parameter that is more than 3 V lower.
Note: A resistance of 6 ohms or greater in the circuit/underhood fuse block will cause the DTC to set.
3. Connect a 20 A fused jumper wire between B+ and the applicable ignition voltage circuit terminal 87 leading to the K20 ECM. Ignition ON, verify that the applicable scan tool parameter displays between 9-14 V.
• If the applicable scan tool parameter is less than the specified value, test the ignition voltage circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
4. Ignition OFF, connect a DMM set to the diode setting between the control circuit terminal 86 and ground. Verify the DMM displays OL.
• If not the specified value, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
5. Ignition ON, verify the DMM displays less than 1 V.
• If not the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
6. If all circuits test normal, replace the applicable relay.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)
* Engine Control Module Programming and Setup (LFW or LFX) Testing and InspectionEngine Control Module Programming and Setup (LSA) Testing and Inspection for ECM replacement, setup, and programming