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 P0107: Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage
DTC P0108: Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
5-Volt Reference | P0107, P0405, P2122, P2138 | P0107 | P0108 | P0106
MAP Sensor Signal | P0107 | P0108 | P0108 | P0106
Low Reference | -- | P0106, P0108 | -- | P0106

### Typical Scan Tool Data

#### MAP Sensor

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Engine operating in Closed Loop Parameter Normal Range: 32-48 kPa
5-Volt Reference | 17 kPa | 15 kPa | 50 kPa
MAP Sensor Signal | 15 kPa | 101 kPa | 101 kPa
Low Reference | -- | 101 kPa | 101 kPa*
* Internal ECM damage may occur if the circuit is shorted to B+.

### Circuit/System Description

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The engine control module (ECM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The ECM provides a ground on the low reference circuit. The MAP sensor provides a signal to the ECM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The ECM detects a low signal voltage at a low MAP, such as during an idle or a deceleration. The ECM detects a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the TP sensor is greater than 28 percent.

### Conditions for Running the DTC

• | The ignition is ON.

• | The DTCs run continuously once the above condition is met.

### Conditions for Setting the DTC

#### P0107

The ECM detects that the MAP is less than 0.3 volt for greater than 1 second.

#### P0108

The ECM detects that the MAP is greater than 4.9 volts for greater than 1 second.

### Action Taken When the DTC Sets

DTCs P0107 and P0108 are Type A DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0107 and P0108 are Type A DTCs.

### Diagnostic Aids

If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.

### 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

#### Special Tools

J 23738-A Vacuum Pump

### Circuit/System Verification

1. Turn all accessories OFF.
2. Engine running , observe the scan tool MAP Sensor parameter. The reading should be between 32-48 kPa.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, and the MAIN fuse removed, disconnect the harness connector at the MAP sensor.
2. Test for less than 5 ohms between the low reference circuit terminal 1 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Install the MAIN fuse. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.

⇒ | If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM.

⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Verify the scan tool MAP sensor parameter is less than 15 kPa.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

5. Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 3. Verify the scan tool MAP sensor parameter is greater than 100 kPa.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

6. If all circuits test normal, test or replace the MAP sensor.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the MAP sensor.
2. Apply 5 volts and ground to the applicable terminals. Test the voltage from the signal circuit to ground. Apply the specified vacuum to the MAP sensor with the J 23738-A vacuum pump.

⇒ | If the voltage is not with in the specified range, replace the MAP sensor.

Vacuum Reading | Values
--- | ---
5 in Hg (17 kPa) | 3.12-3.20 Volts
10 in Hg (34 kPa) | 2.38-2.50 Volts
15 in Hg (51 kPa) | 1.65-1.75 Volts
20 in Hg (68 kPa) | 0.94-1.02 Volts

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Manifold Absolute Pressure Sensor Replacement

• | Control Module References for ECM replacement, setup, and programming