GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The supercharger boost pressure is monitored and regulated under various engine operating conditions. The powertrain control module (PCM) controls the boost pressure using and output driver module (ODM) and the supercharger boost control solenoid. The supercharger boost control solenoid is connected inline with a vacuum hose, which when commanded, allows boosted air pressure to flow to the bypass valve actuator opening the bypass valve and reducing supercharger boost pressure. Power to the solenoid is supplied through a fuse. The ground circuit is controlled through the ODM. The PCM is capable of monitoring the voltage level on an ODM circuit. If the PCM detects an improper voltage level on the supercharger boost control solenoid control circuit, DTC P0243 sets.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

    • An improper voltage level has been detected on the boost control solenoid control circuit.
    • The above condition is present for at least 30 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 not illuminate.
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
    • The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

    • 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 non-emission related diagnostic.
    • Clear the DTC with a scan tool.

Diagnostic Aids

    • For further system diagnosis, refer to Boost Control System Diagnosis .
    • If the condition is intermittent, refer to Intermittent Conditions .

Test Description

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

  1. This test can detect a partially shorted coil which would cause excessive current flow. Leaving the circuit energized for 2 minutes allows the coil to warm up. When warm, the coil may open, and the amps drops to 0 or the coil may short, and the amps go above 800 mA.

  2. This step tests for a short to voltage on the control circuit.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Command the boost control solenoid ON and OFF using the scan tool.

Do you hear a click when you command the solenoid ON and OFF?

--

Go to Step 3

Go to Step 4

3

  1. Turn OFF the ignition.
  2. Disconnect the powertrain control module (PCM) connector containing the boost control solenoid control circuit. Refer to Powertrain Control Module Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Measure current from the boost control solenoid control circuit in the PCM harness connector to ground for 2 minutes with a DMM on the 10-amp scale.

Does the current remain within the specified value?

0.05-0.8 A (50-800 mA)

Go to Diagnostic Aids

Go to Step 8

4

  1. Turn OFF the ignition.
  2. Disconnect the boost control solenoid.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage between the boost control solenoid control circuit at the solenoid harness connector and a good ground with a DMM.

Is voltage at the specified value?

0 V

Go to Step 5

Go to Step 10

5

  1. Turn OFF the ignition.
  2. Disconnect the boost control solenoid harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the control terminal and the ignition 1 voltage terminal of the boost control solenoid harness connector.
  5. Command the boost control solenoid ON and OFF using the scan tool.

Does the test lamp turn ON and OFF with each command?

--

Go to Step 8

Go to Step 6

6

  1. Turn ON the ignition, with the engine OFF.
  2. Probe the ignition 1 voltage circuit of the boost control solenoid harness connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 12

7

  1. Turn the ignition OFF.
  2. Reconnect the boost control solenoid.
  3. Disconnect the PCM connector containing the boost control solenoid control circuit. Refer to Powertrain Control Module Replacement .
  4. Turn ON the ignition, with the engine OFF.
  5. Probe the boost control solenoid control circuit in the PCM harness connector with a 3-amp fused jumper wire connected to a good ground. Refer to Using Fused Jumper Wires in Wiring Systems.

Does the solenoid operate, audible click?

--

Go to Step 11

Go to Step 9

8

Inspect for a poor connection at the boost control solenoid harness connector and repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 15

Go to Step 13

9

Repair the boost control solenoid control circuit for an open or short to ground. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 15

--

10

Repair the boost control solenoid control circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 15

--

11

Inspect for a poor connection at the PCM harness connector containing the boost control solenoid control circuit and repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 15

Go to Step 14

12

Repair the open or short to ground in the boost control solenoid ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 15

--

13

Replace the boost control solenoid. Refer to Boost Control Solenoid Replacement .

Did you complete the replacement?

--

Go to Step 15

--

14

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 15

--

15

  1. Clear the DTC 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 16

16

Observe the Capture Info with a scan tool.

Are there any DTC that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK