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Home >> Chevy Truck >> 2007 >> Express 3500 V8-6.6L DSL Turbo VIN 6 >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P003A

P003A



DTC P003A

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC Descriptor

DTC P003A
- Turbocharger Boost Control Position Not Learned

Diagnostic Fault Information






Circuit/System Description

The engine control module (ECM) performs the turbocharger (TC) learn procedure automatically when the enabling criteria's have been met. After each ignition cycle, and before the enable criteria have been met, the ECM will use the previously learned value. If the ECM does not have a previously learn value, it will default to a stored calibrated value.

The ECM performs the self learn by commanding the TC vanes to 0 percent, then to 100 percent, while monitoring the TC vane position sensor.

The positions of the TC vanes are controlled by the ECM. The ECM utilizes a TC vane control solenoid and a TC vane position sensor to control the TC vanes. The ECM will vary the boost dependant upon the load requirements of the engine. The vane control solenoid has 2 circuits, a high voltage control circuit and a low voltage control circuit. The ECM uses a pulse width modulation (PWM) on the high control and low control circuits to control the solenoid. The ECM will detect if the automatic TC learn has failed if the commanded vane position did not match the actual vane position by a calibrated threshold.

Conditions for Running the DTC

* DTCs P0107, P0108, P0117, P0118, P2563, P2564, P2565, P2228, P2229 are not set.
* The battery voltage is equal to or greater than 11 volts.
* The ECM is commanding the turbocharger vanes open or closed during a position learn process.
* The engine speed is between 600-750 RPM.
* The engine coolant temp (ECT) is between 73-96°C (163-205°F).
* The calculated fuel rate is less than 30 cu.mm;.
* DTC P003A runs once per key cycle when the above conditions are met.

Conditions for Setting the DTC

The ECM did not detect a valid learn within 30 seconds.

Action Taken When the DTC Sets

DTC P003A is a Type B DTC.

Conditions for Clearing the DTC

DTC P003A is a Type B DTC.

Diagnostic Aids

* If there is a loss of ignition voltage to the ECM terminal C1-76 this DTC may set. Verify this circuit is not shorted to ground/open, or the supply fuse for this circuit is not open.
* If any service has been performed on the turbocharger or on the turbocharger components, a turbocharger relearn must be performed. Failure to perform the turbocharger learn procedure may cause other DTCs to set. Refer to Turbocharger Learn. Programming and Relearning

Circuit/System Verification

1. Verify that DTCs P0047, P0048, P0652, P0653, P0698, P0699, P2564, or P2565 are not set.

• If any of the DTCs are set, Refer to Diagnostic Trouble Code (DTC) List - Vehicle. Diagnostic Trouble Code Descriptions

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 Records data.

Circuit/System Testing

Important: 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. Connect the J 34730-405 between the high control Terminal A and the low control circuits Terminal B.

Important: 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 engine coolant temperatures are above 70°C (158°F), the test lamp will flash ON and OFF without commands from a scan tool.

3. 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 change from bright to dim when changing between the commanded states.

• If the test lamp does not change brightness, test the low control circuit Terminal A for a short to voltage. If the circuit tests normal, test the low control Terminal A and high control circuits Terminal B for a short to ground or an open/high resistance. If the circuits test normal, replace the ECM.

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

4. Ignition OFF, measure the resistance of the TC control solenoid. The reading should be between 3-7 ohms.

• If the resistance is not within the specified range, replace the TC control solenoid.

5. 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.

6. Disconnect the harness connectors at the ECM, and TC vane position sensor.
7. Test for less than 5 ohms of resistance on all circuits between the following terminals:

* The ECM C1 TC solenoid high control circuit terminal 48 to TC control solenoid terminal A.
* The ECM C1 TC solenoid low control circuit terminal 96 to TC control solenoid terminal B.
* The ECM C1 TC sensor signal circuit terminal 20 to TC position sensor terminal B.
* The ECM C1 TC sensor low reference terminal 63 to TC position sensor terminal C.
* The ECM C1 TC sensor 5-volt reference terminal 13 to TC position sensor terminal D.

• If greater than the specified range, repair the high resistance in the affected circuit.

8. Connect the ECM connectors. Test the TC vane position sensor.
9. Install and connect the TC vane position sensor.
10. Inspect the turbocharger for debris, damage, or sticking vanes.
11. If all circuits, the TC control solenoid, and the TC vane position sensor tests are normal, replace the turbocharger assembly.

Component Testing

Important: You must perform the Circuit/System Testing in order to verify the integrity of the TC vane position sensor circuits 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 position sensor while observing the TC Vane Position Sensor parameter on the scan tool for a smooth decreasing percentage from 100-0 percent without any spikes or dropouts.

• If the TC Vane Position Sensor parameter is erratic, replace the TC vane position sensor.

Repair Instructions

* Turbocharger Vane Position Sensor Replacement
* Turbocharger Control Solenoid Valve Replacement
* Turbocharger Replacement (LLY, LBZ) Turbocharger Replacement (LMM)
* Control Module References for ECM replacement, setup, and programming 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.
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