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 | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
5-Volt Reference | P0107, P0452, P0532, P0641 | P0106, P0107 | P0107 | P0106, P0108, P0453, P0533, P0641 | P0106, P0107
MAP Sensor Signal | P0107 | P0106, P0107 | P0107 | P0108 | P0106, P0107, P1101
Low Reference | -- | P0106, P0108 | P0106, P0108 | -- | P0106, P0108

### Typical Scan Tool Data

#### MAP Sensor

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Engine Running Parameter Normal Range: 12-103 kPa
5-Volt Reference | 10 kPa | 10 kPa | 104 kPa
MAP Sensor Signal | 10 kPa | 10 kPa | 104 kPa
Low Reference | -- | 80-103 kPa | --

### Circuit Description

The manifold absolute pressure (MAP) sensor measures the pressure inside the intake manifold. Pressure in the intake manifold is affected by engine speed, throttle opening, intake air temperature (IAT), and barometric pressure (BARO). A diaphragm within the MAP sensor is displaced by the pressure changes that occur from the varying load and operating conditions of the engine. The sensor translates this action into electrical resistance. The MAP sensor wiring includes 3 circuits. The engine control module (ECM) supplies a regulated 5 volts to the sensor on a 5-volt reference circuit. The ECM supplies a ground on a low reference circuit. The MAP sensor provides a signal voltage to the ECM, relative to the pressure changes, on the MAP sensor signal circuit. The ECM converts the signal voltage input to a pressure value.

Under normal operation the greatest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor to determine the current BARO. The least manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 12 kPa, when pressures are less, to as great as 103 kPa, depending on the current BARO. The ECM monitors the MAP sensor signal for pressure outside of the normal range.

### Conditions for Running the DTC

#### P0107

• | DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0641, P0651, P2135 are not set.

• | The throttle angle is greater than 0 percent when the engine speed is less than 1,000 RPM.

| OR

• | The throttle angle is greater than 13 percent when the engine speed is greater than 1,000 RPM.

• | This DTC runs continuously within the enabling conditions.

#### P0108

• | DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0641, P0651, P2135, are not set.

• | The engine has been running for a period of time that is determined by the start-up engine coolant temperature (ECT). The time ranges from 8 seconds at less than -30°C (-22°F) to 3 seconds at greater than 30°C (86°F).

• | The throttle angle is less than one percent when the engine speed is less than 1,200 RPM.

| OR

• | The throttle angle is less than 20 percent when the engine speed is greater than 1,200 RPM.

• | This DTC runs continuously within the enabling conditions.

### Conditions for Setting the DTC

#### P0107

The ECM detects that the MAP sensor voltage is less than 0.10 volt for more than 4 seconds.

#### P0108

The ECM detects that the MAP sensor voltage is more than 4.90 volts for more than 4 seconds.

### Action Taken When the DTC Sets

DTCs P0107 and P0108 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0107 and P0108 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Controls Connector End Views

• | Engine Control Module Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Output Controls

#### Special Tools Required

• | J 23738-A Mityvac

• | J 35555 Metal Mityvac

### Circuit/System Verification

1. If P0641 or P0651 are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
2. Ignition OFF for 90 seconds, determine the current vehicle testing altitude. Ignition ON, observe the scan tool BARO parameter. Compare the parameter to the Altitude Versus Barometric Pressure table. The BARO parameter should be within the specified range as indicated in the table.
3. Use the scan tool and compare the MAP Sensor parameter to a known good vehicle, under various operating conditions.
4. Ignition ON, observe the scan tool MAP sensor parameter. Start the engine. The MAP Sensor parameter should change.

⇒ | Operate the vehicle within the Conditions fro Running the DTC. 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, disconnect the MAP harness connector at the MAP sensor.
2. Ignition OFF for 90 seconds, test for less than 5 ohms of resistance between the low reference circuit terminal A and ground.

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

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

⇒ | If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

⇒ | If greater than 5.2 volts 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 12 kPa.

⇒ | If greater than 12 kPa, 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 and the 5-volt reference circuit terminal C. Verify the scan tool MAP Sensor parameter is greater than 103 kPa.

⇒ | If less than 103 kPa, test the signal circuit terminal B 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

Important: You must perform the circuit/system testing, in order to verify the integrity of the MAP sensor circuits, before proceeding with the component testing.

#### Erratic Signal Test

1. Ignition OFF, remove the MAP sensor.
2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal C and the corresponding terminal of the MAP sensor.
3. Install a jumper wire between the low reference circuit terminal A of the MAP sensor and ground.
4. Install a jumper wire at terminal B of the MAP sensor.
5. Connect a DMM between the jumper wire from terminal B of the MAP sensor and ground.
6. Ignition ON, with the J 23738-A or J 35555 , slowly apply vacuum to the sensor while observing the voltage on the DMM. The voltage should vary between 0-5.2 volts without any spikes or dropouts.

⇒ | If the voltage reading is erratic, replace the MAP sensor.

### 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