GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The position of the turbocharger vanes is controlled by the engine control module (ECM). The ECM utilizes a turbocharger vane control solenoid valve and a turbocharger vane position sensor to control the turbocharger vanes. When the engine is not under load, the turbocharger vanes are in an open position, or no boost condition. When the engine is under load, the ECM commands the control solenoid valve to close the turbocharger vanes, thus increasing the boost. The ECM will vary the boost dependant upon the load requirements of the engine. The vane position sensor uses the following 3 circuits:

    • A 5-volt reference circuit
    • A low reference circuit
    • A signal circuit

The ECM provides the sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Movement of the sensor from the closed position to the open position provides the ECM with a signal voltage through the position sensor signal circuit. If the ECM detects an excessively high position sensor signal voltage, DTC P2565 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2565 Turbocharger Vane Control Position Sensor Circuit High Voltage

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

    • The ECM detects that the turbocharger vane position sensor signal voltage is more than 3.9 volts.
    • The above condition exists for more than 6 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 3 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.

Step

Action

Values

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 - Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

  1. Turn ON the ignition, with the engine OFF.
  2. Monitor the Diagnostic Trouble Code (DTC) Information with the scan tool.

Is DTC P0653 also set?

--

Go to DTC P0653

Go to Step 3

3

  1. Start the engine.
  2. Select the TC Vane Position Sensor test in Scan Tool Output Controls.
  3. With the engine at idle, observe the TC vane position sensor and the desired TC vane position while commanding the TC vane position sensor to 100 percent with the scan tool.

Is the TC vane position at or near the desired TC vane position while commanding the TC vane position sensor from 0-100 percent?

--

Go to Step 4

Go to Step 5

4

  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 5

Go to Intermittent Conditions

5

  1. Turn OFF the ignition.
  2. Disconnect the turbocharger vane position sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the signal circuit to the low reference circuit with a DMM.

Is the voltage less than the specified value?

4.8 V

Go to Step 7

Go to Step 6

6

Is the voltage more than the specified value?

5.2 V

Go to Step 11

Go to Step 8

7

Measure the voltage from the signal circuit to a good ground with a DMM.

Is the voltage less than the specified value?

4.8 V

Go to Step 12

Go to Step 10

8

Measure the current between the 5-volt reference circuit and the low reference circuit at the TC vane position sensor connector, with a DMM

Is the current less than the specified value?

170 mA

Go to Step 9

Go to Step 13

9

Test the vane position sensor low reference circuit for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

10

Test the vane position sensor low reference circuit for an open and for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

11

Important: Disconnecting the engine control module (ECM) may eliminate the short during testing.

Test the vane position sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

12

Test the vane position sensor signal circuit for an open and for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 14

13

Test for an intermittent and for a poor connection at the vane position sensor. 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 17

Go to Step 15

14

Test for an intermittent and for a poor connection at the ECM. 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 17

Go to Step 16

15

Replace the turbocharger vane position sensor. Refer to Turbocharger Vane Position Sensor Replacement .

Did you complete the replacement?

--

Go to Step 17

--

16

Replace the ECM. Refer to Engine Control Module Replacement .

Did you complete the replacement?

--

Go to Step 17

--

17

  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Perform the turbocharger learn procedure. Refer to Turbocharger Learn .
  5. 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 18

18

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List

System OK