• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Ignition 1 Voltage, Powertrain Relay | P0689 | P0689, P1682 | P0690 | -- |
Ignition 1 Voltage, Run/Crank Relay | -- | P1682 | -- | -- |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Ignition ON, engine OFF, and run/crank and powertrain relay are commanded ON | |||
Ignition 1 Voltage, Run/Crank | 0 Volts | 0 Volts | 12 Volts |
EC Ignition (Powertrain) Relay Feedback Signal | 0 Volts | 0 Volts | 12 Volts |
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 run/crank 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.
• | 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. |
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.
DTC P1682 is a Type A DTC.
DTC P1682 is a Type A DTC.
This test procedure requires that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test.
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
J 35616 GM-Approved Terminal Test kit
⇒ | If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F. |
Important: On the scan tool, the powertrain relay is referred to as the EC ignition relay.
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
⇒ | If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F. |
⇒ | If the test lamp illuminates, test the powertrain relay controlled output circuit for a short to voltage. |
⇒ | 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. |
⇒ | If the test lamp does not illuminate, test the powertrain relay switch voltage supply circuit for an open/high resistance. |
⇒ | 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. |
⇒ | 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. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.