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Pete
Pete, Auto Service Technician
Category: Chevy
Satisfied Customers: 24728
Experience:  14 years GM dealer Technician.
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P003a code, P003a--states that the turbo charger must go

Customer Question

p003a code
JA: Just to clarify, what's the exact code? And have you tried to reset it?
Customer: P003a--states that the turbo charger must go thru a relearn. There were two codes first. the P003a and the P2563-00. However, after clearing the codes and then finding the first code to come back.
JA: What is the model/year of your Chevy?
Customer: 06 GMC 3500
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I just bought the truck and while driving home, the check engine light lit. I was told by the dealer to clear the codes and see what comes back. I have scanners, but not one that has the capability to relearn the turbo
JA: Anything else you think the mechanic should know?
Customer: The dealer that I bought the truck from is 200 miles away. I am trying to solve the issue myself, but would take the truck back to the dealer and have him fix it. I am a car mechanic and familiar with scan tools but not a diesel mechanic.
Submitted: 3 months ago.
Category: Chevy
Expert:  Pete replied 3 months ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

This may be a failed component like the turbo charger itself when these codes set which can be common.Here is the diagnostic procedure for the P003a code.You may want the dealer to diagnose and repair this if it is a failed turbo.

Circuit/System Verification

1. If DTC P0652, P0653, P0698, P0699, P2564, or P2565 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis See: A L L Diagnostic Trouble Codes ( DTC ) > Diagnostic Trouble Code Descriptions > Diagnostic Trouble Code (DTC) Type Definitions.
2. Engine running, increase the engine speed to 1,500 RPM and maintain. Command the TC Vane Pos. Ctrl. Solenoid ON and OFF with a scan tool. Observe the Vane Position Sensor parameter. The TC Vane Position Sensor parameter should increase to 95-97 percent and decrease to near 0 percent when commanded ON and OFF.
3. Engine running, observe the TC Vane position Sensor and the Desired TC Vane Position parameters with a scan tool. Slowly increase the engine speed from idle to 2,500 RPM, and slowly return the engine to idle speed. The TC Vane Position Sensor parameter should remain near or equal to the Desired TC Vane Position parameter throughout the engine speed range.
4. Engine running, observe the TC Vane Position Sensor and the Desired TC Vane Position parameters while increasing the TC vane position in 5 percent increments from 0-100 percent with a scan tool. The parameters should remain within 2 percent of each other during the entire range.
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 data.

Circuit/System Testing

Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, for 90 seconds, disconnect the harness connector at the TC control solenoid.
2. Ignition ON, verify that a test lamp illuminates between the TC high control circuit terminal A and ground.
- If the test lamp does not illuminate, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
3. Connect the J 34730-405 between the high control terminal A and the low control circuits terminal B.

Note: When the engine coolant temperature is less than 70°C (158°F), the test lamp will change brightness when commanded with a scan tool. When the ECM is attempting a TC Learn, the test lamp will flash ON and OFF without commands from a scan tool.

4. Engine running, engine coolant temperature (ECT) sensor 1 must be less than 70°C (158°F). Command the TC Vane Pos. Ctrl. solenoid ON and OFF with a scan tool. The test lamp should illuminate and change from bright to dim when changing between the commanded states.
- If the test lamp does not illuminate, test the low control circuit terminal B for an open/high resistance or a short to voltage. If the circuit tests normal, replace the ECM.
- If the test lamp remains illuminated, test the low control circuit terminal B for a short to ground. If the circuit tests normal, replace the ECM.

Note: The resistance of the TC control solenoid will vary with the temperature.

5. Ignition OFF, measure the resistance of the TC control solenoid. The reading should be between 3-7 .
- If the resistance is not within the specified range, replace the TC control solenoid.
6. Test for infinite resistance between each TC control solenoid terminal and the TC control solenoid housing.
- If less than infinite resistance, replace the TC control solenoid.
7. Disconnect the harness connectors at the ECM, and TC vane position sensor.
8. Test for less than 5 on all turbocharger sensor and solenoid circuits between the following terminals:
- The ECM X1 TC solenoid high control circuit terminal 48 to TC control solenoid terminal A.
- The ECM X1 TC solenoid low control circuit terminal 96 to TC control solenoid terminal B.
- The ECM X1 TC sensor signal circuit terminal 20 to TC position sensor terminal B.
- The ECM X1 TC sensor low reference terminal 63 to TC position sensor terminal C.
- The ECM X1 TC sensor 5 V reference terminal 13 to TC position sensor terminal D.
- If greater than the specified range, repair the high resistance in the affected circuit.
9. Connect the ECM connectors. Test the TC vane position sensor. Refer to Component Testing in this document for instructions.
10. Install and connect the TC vane position sensor.
11. Command the turbocharger TC Vane Position Sensor from 0 percent to 100 percent while observing the TC Vane Position Sensor Volts parameter. The voltage should increment smoothly and gradually from approximately 1.0 V at 0 percent to greater than 3.5 V at 100 percent.
- If the voltage parameter does not change gradually and smoothly, replace the TC control solenoid.
12. Inspect the turbocharger for debris, damage, or sticking vanes. Refer to Turbocharger Cleaning and Inspection See: Engine > Overhaul.
13. If all circuits, the TC control solenoid, and the TC vane position sensor tests are normal, replace the turbocharger assembly.

Component Testing

Note: You must perform the Circuit/System Testing before proceeding with the Component Testing.

TC Vane Position Sensor

1. Ignition OFF, remove the TC vane position sensor.
2. Connect the harness connector to the TC vane position sensor.
3. Ignition ON, slowly depress the button on the end of the TC vane sensor. Observe the TC vane position sensor parameter for a smooth decreasing percentage from 100-0 percent without any spikes or dropouts.
- If the TC Vane Position Sensor parameter does not increment smoothly, replace the TC vane position sensor.

Repair Instructions

- Turbocharger Vane Position Sensor Replacement See: Turbocharger > Procedures
- Turbocharger Control Solenoid Valve Replacement See: Turbocharger > Procedures
- Control Module References for ECM replacement, setup, and programming See: Turbocharger > Programming and Relearning

Repair Verification

1. Engine running, observe the scan tool TC Vane Position Sensor and the Desired TC Vane Position parameters. Slowly increase the engine speed to 2,500 RPM, and slowly return the engine speed to an idle. The TC Vane Position parameter should remain near or equal to the Desired TC Vane Position parameter.
2. Engine running, observe the scan tool TC Vane Position Sensor parameter while increasing the engine speed to 1,500 RPM and maintaining. Command the TC Vane Pos. Ctrl. Solenoid ON and OFF. The TC Vane Position Sensor parameter should increase to 95-97 percent when the TC solenoid is commanded ON, and decrease to near 0 percent when commanded OFF.
3. Engine running, observe the scan tool TC Vane Position Sensor and the Desired TC Vane Position parameters while increasing the TC vane position sensor in 5 percent increments from 0-100 percent. The TC Vane Position Sensor and the Desired TC Vane Position parameters should remain within 2 percent of each other during the entire range.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete