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 Descriptors

DTC P0068: MAP/MAF - Throttle Position Correlation

### Circuit/System Description

The engine control module (ECM) uses the following information to calculate an expected airflow rate:

• | The throttle position (TP) sensor.

• | The manifold absolute pressure (MAP) sensor.

• | The intake air temperature (IAT) sensor.

• | The engine RPM.

### Conditions for Running the DTC

• | DTCs P0641, P0651, P1516, P2101 or P2119 are not set.

• | The engine is running.

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

### Conditions for Setting the DTC

The ECM detects that the throttle position and the indicated engine load do not correspond with the expected load and throttle position for less than 1 second.

### Action Taken when the DTC Sets

DTC P0068 is a type A DTC.

### Conditions for Clearing the MIL/DTC

DTC P0068 is a type A DTC.

### Reference Information

#### 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

### Circuit/System Testing

1. Inspect for the following conditions:

• | Vacuum hoses for splits, kinks and correct connections as shown on Vehicle Emission Control Information label.

• | Inspect thoroughly for any type of leak or restriction.

• | Air leaks at throttle body mounting area and intake manifold sealing surfaces.

2. Inspect the throttle body for the following conditions:

• | Loose or damaged throttle blade.

• | Broken throttle shaft.

• | Any throttle body damage.

⇒ | If any of these conditions exist, replace the throttle body assembly.

3. Using a scan tool allow the engine to reach normal operating temperature. Observe the MAP and MAF Sensor parameters.
4. Take a snapshot of the engine data list while performing the actions listed below.

• | Idle the engine.

• | Increase the engine speed slowly to 3,000 RPM, then back to idle.

• | Exit from the snapshot and review the data.

• | Observe the MAP/MAF/TP sensor parameters frame by frame. The MAP/MAF/TP sensor parameters should change smoothly and gradually as the engine speed is increased and is returned to idle.

⇒ | If the MAP/MAF/TP sensor parameters do not change smoothly and gradually as the engine speed is increased and is returned to idle, identify the senor at fault and replace the appropriate sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification.

• | Throttle Body Assembly Replacement

• | Engine Control Module Replacement for engine control module replacement, setup and programming.