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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P2565

Circuit Description

The variable nozzle turbocharger (VNT) position sensor is a linear variable differential transtrometer type sensor. The VNT position sensor generates voltage according to VNT position and the generated voltage is input to the engine control module (ECM) for the VNT position sensor signal. The VNT position sensor has the following circuits:

    • The 5-volt reference circuit
    • The low reference circuit
    • The VNT position sensor signal circuit

The ECM supplies 5 volts to the VNT position sensor on the 5-volt reference circuit. The ECM also provides a ground on the low circuit. The VNT position sensor provides a signal to the ECM on the VNT position sensor signal circuit which is relative to the position changes of the VNT. The ECM monitors the VNT position sensor signals for voltage outside the normal range of the VNT position sensor. If the ECM detects an excessively low VNT position sensor signal voltage, this DTC will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P2565 Turbocharger Boost Control Position Sensor Circuit High Voltage

Conditions for Running the DTC
    • The ignition is ON.
    • The battery voltage is between 10-16 volts.

Conditions for Setting the DTC

The VNT position sensor signal circuit voltage is less than 4.9 volts.

Action Taken When the DTC Sets
    • The ECM illuminates the malfunction indicator lamp (MIL) and reduced engine power indicator lamp, if fitted, when the diagnostic runs and fails.
    • The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records.
    • The ECM limits fuel injection quantity for fail-safe operation.
    • The ECM limits fuel rail pressure for fail-safe operation.
    • The ECM closes the exhaust gas recirculation (EGR) valve and stops the EGR control.
    • The ECM limits the VNT control solenoid operation.
    • The ECM inhibits cruise control.

Condition for Clearing the DTC
    • A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
    • Clear the MIL and the DTC with a scan tool.

Diagnostic Aids
    • If an intermittent condition is suspected, the following may cause an intermittent:
       - Poor connections
       - A misrouted harness
       - Rubbed through wire insulation
       - Broken wire inside the insulation
    • Inspect for the following conditions:
       - Poor connection at ECM--Inspect the harness connectors for the following conditions:
   • Backed-out terminals
   • Improper mating
   • Broken locks
   • Improperly formed or damaged terminals
   • Poor terminal to wire connection
       - Damaged harness--Inspect the wiring harness for damage. If the harness appears to be OK, observe the DTC P2565 display on the scan tool while moving the connectors and the wiring harness related to the sensor. A change in the display will indicate the location of the fault.

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn OFF the ignition.
  2. Disconnect the vane position sensor connector.
  3. Connect a 3-amp fused jumper wire between the 5-volt reference circuit and the signal circuit of the vane position sensor.
  4. Turn ON the ignition, with the engine OFF.
  5. Observe the vane position sensor parameter with a scan tool.

Is the vane position parameter more than the specified value?

90%

Go to Step 4

Go to Step 3

3
  1. Observe the Failure Records data 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 for 30 seconds.
  2. Start the engine.
  3. Monitor the DTC information with a scan tool.

Is DTC P0641 also set?

--

Go to Step 5

Go to Step 8

5
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the vane position sensor parameter with a scan tool.

Is the vane position sensor parameter less than the specified value?

10%

Go to DTC P0641

Go to Step 8

6
  1. Turn OFF the ignition.
  2. Disconnect the vane position sensor connector.
  3. Connect a 3-amp fused jumper wire between the 5-volt reference circuit and the signal circuit of the vane position sensor.
  4. Turn On the ignition, with the engine OFF.
  5. Observe the vane position sensor parameter with a scan tool.

Is the vane position sensor parameter more than the specified value?

90%

Go to Step 8

Go to Step 7

7
  1. Turn OFF the ignition.
  2. Disconnect the vane position sensor connector.
  3. Connect the DMM between the 5-volt reference circuit and the low reference circuit of the vane position sensor.
  4. Turn ON the ignition, with the engine OFF.

Is the DMM voltage within the specified range?

4.5-5.5 V

Go to Step 8

Go to Step 9

8

Important: The vane position sensor may be damaged if the circuit short to voltage source.

  1. Test the signal circuit between the engine control module (ECM) and the vane position sensor for a short to voltage circuit and an open circuit.
  2. Repair the circuits as necessary.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 10

9
  1. Test the low reference circuit between the ECM and the vane position sensor for an open or high resistance.
  2. Repair the circuits as necessary.

Did you find and correct the condition?

--

Go to Step 14

Go to Step 11

10
  1. Turn OFF the ignition.
  2. Disconnect the vane position sensor connector.
  3. Inspect for poor connections at the harness connector of the vane position sensor.
  4. Repair the connections as necessary.

Did you find and correct the condition?

 

Go to Step 14

Go to Step 12

11
  1. Turn OFF the ignition.
  2. Disconnect the ECM.
  3. Inspect for connections at the harness connector of the ECM.
  4. Repair the connections, as necessary.

Did you find and correct the condition?

 

Go to Step 14

Go to Step 13

12

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

Did you complete the replacement?

--

Go to Step 14

--

13

Important: The new ECM must be programmed.

Replace the ECM. Refer to Engine Control Module Programming and Setup , Engine Control Module Replacement/Restore Fuel Rate Data , and Fuel Injector Flow Rate Programming .

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. 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 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

System OK