Circuit Description
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). When the ECM commands the powertrain relay ON, ignition 1 voltage is supplied to the ECM through the ECM 2 fuse in the underhood fuse block. This ignition 1 voltage input to the ECM provides the ignition power for the throttle actuator control (TAC) circuitry, and is also used to confirm the powertrain relay contacts have closed. This DTC will set when the ECM detects less than 10 volts on the ignition 1 voltage circuit to the ECM, after the ignition switch is turned ON. DTC P0689 indicates an open, high resistance, or short to ground in the ignition 1 voltage circuit to the ECM.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0689 Engine Controls Ignition Relay Feedback Circuit Low Voltage
Conditions for Running the DTC
| • | The battery voltage is between 9-16 volts. |
| • | The ignition switch is turned ON. |
| • | The powertrain relay has been commanded ON. |
Conditions for Setting the DTC
The ECM detects less than 10 volts on the ECM 2 ignition 1 voltage circuit for 5 seconds.
Action Taken When the DTC Sets
| • | The control module stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will illuminate. |
| • | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in Failure Records. |
| • | The driver information center, if equipped, may display a message. |
Conditions for Clearing the MIL/DTC
| • | A current DTC, last test failed clears when the diagnostic runs and passes. |
| • | A history DTC clears 40 consecutive warm-up cycles, if no other failures are reported or any other emission related diagnostic. |
| • | Clear the DTC with a scan tool. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views and Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections |
3 |
Does the test lamp illuminate on both test points of the ECM 2 fuse? | -- | Go to Step 7 | Go to Step 4 |
4 | Does the test lamp illuminate on one test point of the ECM 2 fuse? | -- | Go to Step 5 | Go to Step 9 |
5 |
Does the test lamp illuminate? | -- | Go to Step 19 | Go to Step 6 |
6 | Test the underhood fuse block bus bar circuit from the ECM 2 fuse to the underhood fuse block electrical connector for a short to ground. Refer to Circuit Testing . Did you find a condition? | -- | Go to Step 21 | Go to Step 18 |
7 |
Does the resistance measure greater than the specified value? | 3 ohms | Go to Step 20 | Go to Step 8 |
8 | Test the underhood fuse block ignition 1 voltage bus bar circuit, from the ECM 2 fuse to the underhood fuse block electrical connector for a high resistance or an open. Refer to Circuit Testing . Did you find a condition? | -- | Go to Step 21 | Go to Step 18 |
9 |
Notice: Refer to Test Probe Notice in the Preface section. Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 11 |
10 | Test the underhood fuse block ignition 1 voltage bus bar circuit, between the powertrain relay and the ECM 2 fuse, for a high resistance or an open. Refer to Circuit Testing . Did you find and condition? | -- | Go to Step 21 | Go to Step 12 |
11 | Probe the mounting stud for the battery positive cable at the underhood fuse block, with a test lamp that is connected to a good ground. Does the test lamp illuminate? | -- | Go to Step 23 | |
12 | Measure the resistance from terminal #85 of the powertrain relay to terminal #86 with a DMM. Refer to Troubleshooting with a Digital Multimeter . Does the resistance measure within the specified value? | 70-110 ohms | Go to Step 13 | Go to Step 22 |
13 | Measure the resistance from terminal #30 of the powertrain relay to terminal #87 with a DMM. Does the DMM display OL? | -- | Go to Step 14 | Go to Step 22 |
14 | Measure the resistance from terminal #30 of the powertrain relay to terminal #85 with a DMM. Does the DMM display OL? | -- | Go to Step 15 | Go to Step 22 |
15 | Measure the resistance from terminal #85 of the powertrain relay to terminal #87 with a DMM. Does the DMM display OL? | -- | Go to Step 16 | Go to Step 22 |
16 |
Does the resistance measure more than the specified value? | 2 ohms | Go to Step 22 | Go to Step 17 |
17 | Test for an intermittent and for a poor connection at the powertrain relay terminals on the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find a condition? | -- | Go to Step 21 | Go to Testing for Intermittent Conditions and Poor Connections |
18 | Test for shorted terminals and poor connections at the ECM electrical connector and the ECM wire harness electrical connector. Refer to Testing for Intermittent Conditions and Poor Connections . Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 23 |
19 | Repair the short to ground in the ignition 1 voltage circuit, between the underhood fuse block wire harness electrical connector and the ECM wire harness electrical connector. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 24 | -- |
20 | Repair the high resistance or an open in the ignition 1 voltage circuit, between the underhood fuse block wire harness electrical connector and the ECM wire harness electrical connector. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 24 | -- |
21 | Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement . Did you complete the replacement? | -- | Go to Step 24 | -- |
22 | Replace the powertrain relay. Refer to Relay Replacement . Did you complete the replacement? | -- | Go to Step 24 | -- |
23 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 24 | -- |
24 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Step 25 |
25 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
