GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2006 🢒 Allure 🢒 Restraints 🢒 SIR 🢒 DTC P2088, P2090, P2092, or P2094

Circuit Description

The camshaft position (CMP) actuator solenoid is pulse width modulated (PWM). The engine control module (ECM) controls the CMP actuator solenoid duty cycle by controlling the amount of solenoid ON time.

Ignition voltage is supplied directly to the CMP actuator solenoid. The ECM controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. If the ECM detects the control circuit voltage is less than a predetermined value when the circuit is commanded OFF, this DTC sets.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC P2088 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 1
    • DTC P2090 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 1
    • DTC P2092 Intake Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 2
    • DTC P2094 Exhaust Camshaft Position (CMP) Actuator Solenoid Control Circuit Low Voltage Bank 2

Conditions for Running the DTC
    • The engine speed is more than 80 RPM.
    • The ignition 1 voltage is between 10-18 volts.
    • The ECM has commanded the CMP actuator solenoid ON and OFF at least once during the ignition cycle.
    • DTC P2088, P2090, P2092, and P2094 runs continuously once the above conditions are met for more than 1 second.

Conditions for Setting the DTC
    • The ECM detects a short to ground in the CMP actuator solenoid circuits.
    • The condition exists for more than 4 seconds.

Action Taken When the DTC Sets
    • The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
    • The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC
    • The control module turns OFF the malfunction indicator lamp (MIL) after 4 consecutive ignition cycles that the diagnostic runs and does not fail.
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

The following table illustrates the ECM connector locations:

ECM Connector Location

C1

C2

Front of Vehicle

    • Use the J 35616-A/BT-8637 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
    • If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the circuit status for the component with a scan tool. The circuit status parameter changes from OK or Indeterminate to Fault if there is a condition with the circuit or a connection. The ODM information is in the output driver module (ODM) data list.
    • If the ignition 1 voltage circuit is shorted to ground, other component DTCs will set.
    • For an intermittent condition, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step determines if the condition exists. The engine speed must be increased to enable the CMP actuator solenoids. The DTC will not set unless the solenoid is commanded ON and OFF at least once during the ignition cycle.

    2.

  2. This step verifies that the ECM is providing a ground to the CMP actuator solenoid.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Start the engine.
  2. Allow the engine to reach operating temperature.
  3. Increase the engine speed to 2,000 RPM for 10 seconds.
  4. Observe the DTC information with a scan tool.

Does DTC P2088, DTC P2090, DTC P2092, or P2094 fail this ignition?

Go to Step 4

Go to Step 3

3
  1. Observe the Freeze Frame/Failure Records for this DTC.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  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 4

Go to Diagnostic Aids

4
  1. Turn OFF the ignition.
  2. Disconnect the camshaft position (CMP) actuator solenoid. Refer to the appropriate procedure:
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition 1 voltage circuit of the CMP actuator solenoid with a test lamp that is connected to the engine control module (ECM) housing.

Does the test lamp illuminate?

Go to Step 5

Go to Step 9

5

  1. Connect a test lamp between the control circuit of the CMP actuator solenoid and the ignition 1 voltage circuit of the CMP actuator solenoid.
  2. Start the engine.
  3. Command the appropriate CMP actuator solenoid from 0 to 40 and back to 0 degrees with a scan tool.
  4. Exit the CMP Actuator Solenoid Control function.
  5. Turn OFF the ignition.

Does the test lamp turn ON when commanded to 40 degrees and OFF when commanded to 0 degrees?

Go to Step 7

Go to Step 6

6

Test the control circuit of the CMP actuator solenoid for a grounded circuit. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 8

7

Test for an intermittent and for a poor connection at the CMP actuator solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 12

Go to Step 11

9

    Important: The ignition 1 voltage circuit supplies voltage to other components. Make sure you test all circuits for a short to ground or test all components for being shorted that share the ignition voltage circuit.

  1. Repair the open or the grounded ignition 1 voltage circuit of the CMP actuator solenoid. Refer to Wiring Repairs .
  2. Replace the fuse if necessary.

Did you complete the repair?

Go to Step 12

--

10

Replace the CMP actuator solenoid. Refer to the appropriate procedure:

Did you complete the replacement?

Go to Step 12

--

11

Replace the ECM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 12

--

12
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  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 2

Go to Step 13

13

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

System OK