P1682
DTC P1682
Diagnostic Instructions
• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Diagnostic System Check - Vehicle
• Review Strategy Based Diagnosis for an overview of the diagnostic approach. Strategy Based Diagnosis
• Diagnostic Procedure Instructions provides an overview of each diagnostic category. Diagnostic Procedure Instructions
DTC Descriptor
DTC P1682 - Ignition 1 Switch Circuit 2
Diagnostic Fault Information
Typical Scan Tool Data
EC Ignition Relay Feedback
Ignition 1 Signal
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 two 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.
* 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 2 seconds.
Action Taken When the DTC Sets
DTC P1682 is a Type B DTC.
Engine may operate in a reduced engine power mode.
Conditions for Clearing the DTC
DTC P1682 is a Type B 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 Electrical Diagrams
• Power Distribution Schematics Power Distribution Diagrams
Connector End View Reference
• Engine Control Module Connector End Views Connector Views
• Engine Controls Connector End Views Connector Views
Description and Operation
Engine Control Module Description Engine Control Module (ECM)
Electrical Information Reference
• Circuit Testing Circuit Testing
• Connector Repairs Connector Repairs
• Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs Wiring Repairs
• Probing Electrical Connectors Probing Electrical Connectors
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
• Scan Tool Data List Scan Tool Data List
• Scan Tool Data Definitions Scan Tool Data Definitions
• Scan Tool Output Controls Scan Tool Output Controls
Circuit/System Verification
1. If DTCs P0685, P0689, P0690, or B1380 are set, diagnose those DTCs first.
2. 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 two parameters.
3. 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.
Circuit/System Testing
1. Ignition ON, observe the Ignition 1 Signal and EC Ignition Relay Feedback scan tool parameters to determine which is less than B+.
2. Ignition OFF, remove the relay that corresponds to the scan tool parameter that is less than B+.
Important: 6 ohms or greater in the circuit/underhood fuse block will cause the DTC to set.
3. 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 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.
4. If all circuits test normal, test or replace the applicable relay.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Refer to Programming and Relearning.Programming and Relearning
* Relay Replacement. Service and Repair