• | 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 | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Battery Supply Voltage - Coil | P0685 | P0685 | P0685 | -- | -- |
Battery Supply Voltage - Armature | P0689 | P0689 | P0689 | -- | -- |
Relay Control Circuit | P0685 | P0685 | P0685 | P0685 | -- |
Relay Feedback Circuit | P0689 | P0689 | P0689 | P0690 | -- |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
---|---|---|---|---|
Operating Conditions: Ignition ON, with the engine OFF | ||||
Battery Supply Voltage - Coil | -- | 0 V | 0 V | -- |
Battery Supply Voltage - Armature | -- | 0 V | 0 V | -- |
EC Ignition Relay Control | -- | 0 V | 0 V | -- |
EC Ignition Relay Feedback | 11.9-12.9 V | 0 V | 0 V | More than 2 V¹ |
¹ DTC P0690 will set if the ECM detects voltage when the ignition is in the OFF position. |
The powertrain/engine controls (EC) ignition relay is a normally open relay. The relay switch is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the relay switch contact at all times. The engine control module (ECM) supplies the ground path to the relay coil control circuit through an output driver module (ODM). The ODM for the relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. When the ECM commands the relay ON, ignition 1 voltage is supplied to fuses in the underhood fuse block.
The ignition 1 voltage that is supplied to the ECM, provides power to the internal ECM circuits associated with the throttle actuator control (TAC) operation. The ECM also monitors the voltage level on the ignition 1 voltage circuit to confirm that the powertrain relay contacts have closed.
• | The battery voltage is between 10.5-18 volts. |
• | The ignition is ON. |
• | The relay has been commanded ON. |
• | These DTCs run continuously when the above conditions have been met. |
• | The battery voltage is between 10.5-18 volts. |
• | The ignition is OFF. |
• | The powertrain relay has been commanded OFF. |
• | These DTCs run continuously when the above conditions have been met. |
• | The commanded state of the ODM and the actual state of the control circuit do not match. |
OR |
• | The ECM detects that the feedback voltage is not within a predicted range when the relay is commanded ON and OFF. |
• | Either condition is present for more than 2 seconds. |
DTCs P0685, P0686, P0687, P0689, and P0690 are Type C DTCs.
DTCs P0685, P0686, P0687, P0689, and P0690 are Type C DTCs.
• | This test procedure assumes that the vehicle battery has passed a load test and is completely charged. Refer to Battery Inspection/Test. |
• | When disconnecting electrical connectors or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the mating electrical terminals for correct tension. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
⇒ | If the test lamp illuminates, test the ignition circuit for a short to voltage. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the B+ circuit for an open/high resistance. |
• | ECM terminal 1 X2 |
• | ECM terminal 2 X2 |
• | ECM terminal 4 X2 |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the circuit for an open/high resistance and a short to ground. If the circuit tests normal and its fuse is open, replace the ECM. |
⇒ | If not the specified value or if the scan tool does not communicate, test the ignition circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified value, test the control circuit for a short to voltage or short to ground. If the circuits test normal, replace the ECM. |
⇒ | If greater than the specified range, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If the resistance is not within the specified range, replace the main relay. |
• | Terminals 30 and 86 |
• | Terminals 30 and 87 |
• | Terminals 30 and 85 |
• | Terminals 85 and 87 |
⇒ | If continuity is detected, replace the main relay. |
⇒ | If the resistance measures more than 2 ohms, replace the main relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |