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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2005 🢒 Envoy - 4WD 🢒 Accessories 🢒 Navigation Systems 🢒 DTC P0690

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 throttle actuator control (TAC) fuse in the underhood fuse block. The ignition 1 voltage input to the ECM provides the ignition power for the TAC circuitry, and is also used to confirm that the powertrain relay has closed. This DTC will set when the ECM detects more than 2 volts on the ignition 1 voltage circuit to the ECM, after the ignition switch is turned OFF. DTC P0690 indicates a short to battery positive voltage in the ignition 1 voltage circuit to the ECM.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0690 Engine Controls Ignition Relay Feedback Circuit High Voltage

Conditions for Running the DTC
    • The battery voltage is between 9-16 volts.
    • The ignition switch is turned OFF.
    • The powertrain relay has been commanded OFF.

Conditions for Setting the DTC

The ECM detects greater than 2 volts on the TAC ignition 1 voltage circuit for more than 2 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 by this or any other emission related diagnostic.
    • Clear the DTC with a scan tool.

Step

Action

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

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
  1. Observe the Freeze Frame/Failure Records for the DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Turn ON the ignition, with the engine OFF.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 3

Go to Intermittent Conditions

3
  1. Turn OFF the ignition.
  2. Remove the powertrain relay from the underhood fuse block with the J 43244 Relay Puller Pliers. Refer to Relay Replacement in Wiring Systems.
  3. Probe either test point of the TAC fuse with a test lamp that is connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp illuminate on either test point of the fuse?

Go to Step 4

Go to Step 6

4
  1. Turn OFF the ignition.
  2. Disconnect the engine control module (ECM) electrical connector that contains the ignition 1 voltage circuit from the TAC fuse. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
  3. Probe either test point of the TAC fuse with a test lamp that is connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp illuminate on either test point of the fuse?

Go to Step 5

Go to Step 9

5
  1. Turn OFF the ignition.

    2. Notice: Refer to Test Probe Notice in the Preface section.

  2. Probe the ignition 1 voltage terminal at the powertrain relay location, on the underhood fuse block, with a test lamp that is connected to a good ground. This terminal is the one that leads from the powertrain relay to the fuses.
  3. Monitor the test lamp.
  4. Remove the following fuses from the underhood fuse block, one fuse at a time:
    5. • The ENG 1 fuse
    • The O2A fuse
    • The O2B fuse
    • The TAC fuse
    • The INJ A fuse
    • The INJ B fuse

Does the test lamp go out when a fuse is removed?

Go to Step 10

Go to Step 13

6

Measure the resistance from terminal #30, of the powertrain relay to terminal #87 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems.

Does the DMM display OL?

Go to Step 7

Go to Step 11

7

Measure the resistance from terminal #30, of the powertrain relay to terminal #85 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems.

Does the DMM display OL?

Go to Step 8

Go to Step 11

8

Measure the resistance from terminal #85, of the powertrain relay to terminal #87 with a DMM. Refer to Troubleshooting with a Digital Multimeter in Wiring Systems.

Does the DMM display OL?

Go to Intermittent Conditions

Go to Step 11

9

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 and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

10

Repair the short to battery positive voltage in the ignition 1 voltage circuit, which caused the test lamp to go out when the fuse for that circuit was removed. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

--

11

Replace the powertrain relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 14

--

12

Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 14

--

13

Replace the underhood fuse block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 14

--

14
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Turn ON the ignition, with the engine OFF.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze/Frame Records.

Did the DTC fail the ignition?

Go to Step 3

Go to Step 15

15

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information

System OK