For 1990-2009 cars

### 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 00: Throttle Body Airflow Performance
DTC P1101 00: Intake Air Flow System Performance

### Circuit/System Description

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

### Conditions for Running the DTC

#### DTC P0068 00

• | The engine speed is greater than 800 RPM.

• | The ignition voltage is greater than 6.0 V.

• | The throttle actuator control system is not in reduced power mode.

• | DTC P0068 00 run continuously when the above conditions are met.

#### DTC P1101 00

• | DTCs P0102 00, P0103 00, P0106 00, P0107 00, P0108 00, P0112 00, P0113 00, P0117 00, P0118 00, P0335 00, P0336 00 are not set

• | The engine speed is between 400 to 6500 RPM

• | The ECT Sensor is between 70 to 125°C (158 to 257°F).

• | The IAT Sensor is between -20 to +125°C (-4 to +257°F).

• | DTC P1101 00 run continuously when the above conditions are met.

### Conditions for Setting the DTC

The ECM detects that the airflow rate is more than the calculated airflow for more than 0.2 s.

### Action Taken When the DTC Sets

• | DTC P0068 00 is a Type A DTC.

• | DTC P1101 00 is a Type B DTC.

### Conditions for Clearing the DTC

• | DTC P0068 00 is a Type A DTC

• | DTC P1101 00 is a Type B DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Testing

1. Verify none of the following conditions exist:

• | The air intake duct system for loose clamps, cracks, or other damage

• | The air intake duct system for being collapsed or restricted

• | The mass airflow sensor is installed correctly. The arrow indicates direction of airflow and the tabs of the hoses and notches of the sensor must be aligned. Refer to Mass Airflow Sensor Replacement

• | Restricted air filter

• | Throttle body for dirt, debris, and coking

• | A damaged throttle body blade or shaft

• | Splits, kinks, or improper connections at the vacuum hoses

• | Missing, restricted, or leaking exhaust components--Refer to Symptoms - Engine Exhaust

• | Vacuum leaks at the intake manifold, throttle body, and injector O-rings

⇒ | If a condition exists, repair as necessary.

2. Ignition ON, observe the diagnostic trouble code (DTC) information with a scan tool. Verify that DTCs P0641 00, P0651 00, P0697 00, or P06A3 00 are not set.

⇒ | If any of the above DTCs are set, refer to DTC P0641, P0651, P0697, or P06A3

3. Determine the current vehicle testing altitude. Compare the MAP sensor pressure parameter to the reading in the LINK (Altitude Versus Barometric Pressure) table. The MAP sensor pressure parameter should be within the specified range indicated in the table.

⇒ | If the MAP sensor pressure is not within the range specified for your altitude, refer to DTC P0106.

4. Engine idling, observe the MAP Sensor parameter. The reading should be between 26 to 52 kPa (3.8 to 7.5 PSI).

⇒ | If not within the specified range, refer to DTC P0106.

5. Use the scan tool snapshot function to take a snapshot of the engine data list while performing the actions listed below.

5.1. | Engine idling

5.2. | Increase the engine speed slowly to 3000 RPM and then back to idle.

5.3. | Exit from the scan tool snapshot and review the data.

5.4. | Observe the mass air flow (MAF) sensor parameter frame by frame with a scan tool. The MAF sensor g/s parameter should change smoothly and gradually as the engine speed is increased and then returned to idle.

⇒ | If the MAF sensor g/s does not change smoothly and gradually, refer to LINK (DTC P0101) for further diagnosis.

5.5. | Close the valve on the J 37287 .

6. If all conditions test normal, test the engine for a mechanical condition. Refer to Symptoms - Engine Mechanical.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Throttle Body Assembly Replacement

• | Air Cleaner Element Replacement