• | 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 |
---|---|---|---|---|
Relay Coil B+ | P0685 | P0685 | -- | -- |
Relay Switch B+ | P1682 | P1682 | -- | -- |
Relay Coil Control | P0685 | P0685 | P0685 | -- |
Relay Ignition Output Ignition 1 Voltage | P1682 | P1682 | P0690 | -- |
Display Parameters | Normal Range | Short to Ground | Open/High Resistance | Short to Voltage |
---|---|---|---|---|
Operating Conditions: Ignition ON, engine OFF, powertrain relay commanded ON. | ||||
EC Ignition Powertrain Relay Circuit Status | OK/Incomplete | Short to GRD/Open | Short to GRD/Open | Short to B+ |
EC Ignition Powertrain Relay Command | ON | ON | ON | ON |
EC Ignition Powertrain Relay Feedback Signal | 12-12.9 V | 0.0 V | 0.0 V | 12-12.9 V |
The powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an output driver module (ODM). The ODM output control is configured to operate as a low side driver for the powertrain relay. The ODM for the powertrain relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. When the ECM commands the powertrain relay ON, ignition 1 voltage is supplied to the ECM, and to several additional circuits.
• | The ignition is ON. |
• | The battery voltage is between 9-16 volts. |
• | This DTC will run with the ignition ON or OFF. |
• | This DTC will run when the powertrain relay is commanded ON or OFF. |
• | DTC P0685 is not set. |
• | The commanded state of the ODM and the actual state of the control circuit do not match. |
• | The condition is present for more than 5 seconds. |
• | The ECM detects more than 16 volts on the ignition 1 voltage circuit to the ECM when the relay is commanded ON. |
• | The ECM detects more than 2 volts on the ignition 1 voltage circuit to the ECM when the relay is commanded OFF. |
• | The condition is present for more than 2 seconds. |
DTC P0685 or P0690 is a Type B DTC.
DTC P0685 or P0690 is a Type B 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
Control Module References for scan tool information
• | J 35616 GM-Approved Terminal Test Kit |
• | J 43244 Relay Puller Pliers |
⇒ | If the hood position does not display Open, refer to Diagnostic Trouble Code (DTC) List - Vehicle for DTC P254F. |
• | Powertrain relay coil control Ckt. Short Gnd Test Status |
• | Powertrain relay coil control Ckt. Open Test Status |
• | Powertrain relay coil control Ckt. Short Volts Test Status |
• | Each parameter should toggle between OK and Not Run or Not Run and OK |
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 does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the battery positive cable to the underhood fuse block. |
⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If not within the specified value, replace the relay. |
⇒ | If the circuit tests normal, replace the ECM. |
⇒ | If the test lamp illuminates, test the relay ignition 1 voltage circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If the test lamp does not illuminate, test the relay switch B+ circuit for a short to ground, or an open/high resistance. If the circuits test normal, and the fuse for the ignition 1 voltage circuit is open, test the ignition 1 voltage circuit to the ECM for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If the parameter does not display B+, test the ignition 1 voltage circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If another DTC is present, refer to Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure. |