GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The suspension control module provides a common ground (low reference) for all four of the shock solenoid valves. The suspension control module monitors the return voltage on the low reference circuit (ground) for a voltage out of range condition.

For a full system schematic refer to: Suspension Controls Schematics .

Conditions for Running the DTC

Continuously with the ignition on.

Conditions for Setting the DTC

The suspension control module senses a low reference voltage out of range condition.

Action Taken When the DTC Sets

    • DTC C0690 will be stored in memory.
    • Disable all shock solenoid valve outputs.
    • The "SERVICE RIDE CONTROL" message will be displayed.

Conditions for Clearing the MIL/DTC

    • The suspension control module senses the correct voltage on the low reference circuit upon the next ignition cycle.
    • A history DTC will clear after not seeing the malfunction for 100 consecutive ignition cycles.
    • Using a scan tool.

Diagnostic Aids

    • The following conditions may cause a malfunction to occur:
    • A open in all four low reference circuits of the shock solenoid valves.
    • A open in the solenoid ground circuit at the suspension control module.
    • A open in G410 or SP410.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Tests whether the condition is module, system, or condition related.

  2. Tests whether the condition has been corrected or identified as specified in the supporting text.

  3. Tests all 4 low reference circuits of the shock solenoid valves for an open.

  4. Tests all 4 control circuits of the shock solenoid valves for an open.

  5. Tests the solenoid ground circuit at the suspension control module, should be less than 0.5 ohm.

  6. Clear DTCs and checks to see if DTC will reset.

Step

Action

Value(s)

Yes

No

1

Did you perform the RTD Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, monitor the DTC Information for DTC C0690 in the Suspension Control Module.

Does the scan tool indicate that DTC C0690 is current?

--

Go to Step 4

Go to Step 3

3

Since most occurrences of this DTC are caused by connector C197 not fully seated, backed out or bent terminal.

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 8

Go to Step 4

4

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within normal operating conditions.

Does the DTC reset?

--

Go to Step 5

System OK

5

Test all 4 shock solenoid valve low reference circuits for an open between solenoids and the suspension control module.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 6

6

Test all 4 shock solenoid valve control circuits for an open between solenoids and the suspension control module.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 7

7

  1. Turn OFF the ignition.
  2. Disconnect the suspension control module connectors.
  3. Test the resistance of the solenoid ground circuit at the suspension control module, should be less than 0.5 ohms.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 9

8

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within normal operating conditions.

Does the DTC reset?

--

Go to Step 9

System OK

9

Replace the suspension control module. Refer to Electronic Suspension Control Module Replacement .

Did you complete the replacement?

--

System OK

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