Buick Regal: DTC P0068 or P1101

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 provides an overview of each diagnostic category.

DTC Descriptor

DTC P0068

Throttle Body Air Flow Performance

DTC P1101

Intake Air Flow System Performance

Circuit/System Description

The engine control module (ECM) compares actual air flow based on throttle position (TP) to a calculated airflow based on manifold absolute pressure (MAP) sensor, and mass air flow (MAF).

Conditions for Running the DTC

DTC P0068

• The engine speed is at least 800 RPM.
• The ignition voltage is at least 6.4 V.
• The DTC runs continuously when the above conditions are met.

DTC P1101

• DTC P0101, P0102, P0103, P0107, P0108, P0111, P0112, P0113, P0116, P0117, P0118, P0128, P0335, or P0336 is not set
• The engine speed is between 575 - 6, 600 RPM
• The engine coolant temperature (ECT) is between -7 to +129ºC (+19 to +264ºF).
• The intake air temperature (IAT) is between -20 to +125ºC (-4 to +257ºF).
• The DTC runs continuously when the above conditions are met.

Conditions for Setting the DTCs

The ECM detects that the actual airflow rate is greater than the calculated airflow.

Action Taken When the DTCs Set

• DTC P0068 is a type A DTC.
• DTC P1101 is a type B DTC.

Conditions for Clearing the DTCs

• DTC P0068 is a type A DTC.
• DTC P1101 is a type B DTC.

Reference Information

Schematic Reference

Engine Controls Wiring Schematics (LTG)

Connector End View Reference

Component Connector End View Index

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Powertrain Component Views

Powertrain Component Views

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, verify that DTC P0641, P0651, P0697, or P06A3 is not set.

• If any of the DTCs are set
• Go to next step: If none of the DTCs are set

2. If you were sent here from DTC P0068, P0106, P0121, P0236, or P1101; refer to Circuit/System Testing.

3. Ignition ON, verify the scan tool Throttle Body Idle Air Flow Compensation parameter is less than 90 %.

• 90 % or greater
• Go to next step: If less than 90 %

4. Verify the scan tool Throttle Position Sensors 1 and 2 Agree/Disagree parameter displays Agree while performing the Throttle Sweep Test with a scan tool.

• If Disagree
• Go to next step: If Agree

5. Determine the current vehicle testing altitude.

6. Verify the scan tool MAP Sensor pressure parameter is within the range specified in the Altitude Versus Barometric Pressure table.

• If the MAP Sensor parameter is not in range

Refer to DTC P0106 for further diagnosis.

• Go to next step: If the MAP Sensor parameter is within range

7. Verify the engine is equipped with a turbocharger.

• If not equipped with a turbocharger

Refer to Step 10.

• Go to next step: If equipped with a turbocharger

8. Verify the scan tool Boost Pressure Sensor parameter is within the range specified in the Altitude Versus Barometric Pressure table.

• If the Boost Pressure Sensor parameter is not in range

Refer to DTC P0236 for further diagnosis.

• Go to next step: If the Boost Pressure Sensor parameter is within range

9. Verify the scan tool Boost Pressure Sensor parameter decreases after starting the engine.

• If the Boost Pressure Sensor parameter does not decrease

Refer to DTC P0236 for further diagnosis.

Go to next step: If the Boost Pressure Sensor parameter does decrease

10. Engine idling, verify the scan tool MAP Sensor pressure parameter is between 26 - 52 kPa (3.8 - 7.5 PSI) and changes with accelerator pedal input.

• If not between 26 - 52 kPa (3.8 - 7.5 PSI) or does not change

Refer to DTC P0106 for further diagnosis.

• Go to next step: If between 26 - 52 kPa (3.8 - 7.5 PSI) and changes

11. Verify the scan tool MAF Sensor g/s parameter changes smoothly and gradually as the engine speed is increased and decreased while performing the actions listed below.

1. Engine idling
2. Perform the scan tool snapshot function.
3. Increase the engine speed slowly to 3, 000 RPM and then back to idle.
4. Exit from the scan tool snapshot and review the data.
5. Observe the MAF Sensor parameter frame by frame with a scan tool.

• If the MAF Sensor parameter does not change smoothly and gradually

Refer to DTC P0101 for further diagnosis.

• Go to next step: If the MAF Sensor parameter changes smoothly and gradually

12. 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.

13. Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing.

• Go to next step: If the DTC does not set

14. All OK

Circuit/System Testing

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

1. Verify the integrity of the entire air induction system by verifying that none of the following conditions exist:

• Any damaged, improperly installed, collapsed, or restricted components
• Improper operation of turbocharger wastegate actuator or bypass valve, where equipped
• Loose clamps, cracks, or other damage
• An air flow restriction
• Restricted air filter
• Splits, kinks, leaks, or improper connections at the vacuum hoses
• Vacuum leaks at the intake manifold, MAP sensor, and throttle body
• Water intrusion
• Any snow or ice buildup, in cold climates
• Contamination of the MAF sensor element
• Missing, restricted, or leaking exhaust components - Refer to Symptoms - Engine Exhaust for further diagnosis.
• If a condition is found

Repair or replace component as appropriate.

• Go to next step: If no condition is found

2. Test the engine for a mechanical condition. Refer to Symptoms - Engine Mechanical for diagnosis.

• If a condition is found

Repair or replace component as appropriate.

• Go to next step: If no condition is found

3. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for engine control module replacement, programming, and setup

READ NEXT: