Buick Regal: DTC P0107 or P0108

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 provide 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

Typical Scan Tool Data

MAP Sensor

MAP Sensor, if equipped with Turbocharger

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, air temperature, barometric pressure (BARO) ; and if equipped turbocharger output. 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 V 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 at ignition ON, engine OFF, which is equal to the BARO. If equipped, a turbocharger can increase the pressure above BARO, when the vehicle is operated at wide-open throttle (WOT). The lowest manifold pressure occurs when the vehicle is idling or decelerating. The ECM monitors the MAP sensor signal for pressure outside of the normal range.

Conditions for Running the DTC

P0107

This DTC runs continuously.

P0108

This DTC runs continuously.

Conditions for Setting the DTC

P0107

The ECM detects that the MAP Sensor voltage is less than 0.15 V for more than 13 ms.

P0108

The ECM detects that the MAP Sensor voltage is more than 4.50 V for greater than 13 ms.

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 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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

GE-23738-A Vacuum Pump

For equivalent regional tools, refer to Special Tools (diagnostic tools) and Special Tools (Mechanical Tools)

Circuit/System Verification

1. Ignition ON, verify that DTC P0641, P0651, P0697, P06A3, or P06D2 is not set.

• If any of the DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

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

2. Determine the current vehicle testing altitude.

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

• If the MAP Sensor parameter is not in range

Refer to Circuit/System Testing for further diagnosis.

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

4. Verify the engine is equipped with a turbocharger.

• If not equipped with a turbocharger

Refer to Step 6.

• Go to next step: If equipped with a turbocharger

5. Engine idling, verify the scan tool MAP Sensor voltage parameter is between 0.3 - 4.8 V and changes with accelerator pedal input.

• If not between 0.3 - 4.8 V or does not change

Refer to Circuit/System Testing.

• Go to next step: If between 0.3 - 4.8 V and changes

Go to next step: Refer to Step 7.

6. Engine idling, verify the scan tool MAP Sensor voltage parameter is between 0.2 - 4.5 V and changes with accelerator pedal input.

• If not between 0.2 - 4.5 V or does not change

Refer to Circuit/System Testing.

• Go to next step: If between 0.2 - 4.5 V and changes

7. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed in the Freeze Frame/Failure Records data.

8. Verify the DTC does not set.

• If any DTC sets

Refer to Circuit/System Testing.

• Go to next step: If no DTC sets

9. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B74 Manifold Absolute Pressure Sensor.

2. Ignition OFF and all vehicle systems OFF. It may take up to 2 min for all vehicle systems to power down. Test for less than 2 Ω between the low reference circuit terminal 2 and ground.

• If 2 Ω or greater

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 Ω in the low reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If less than 2 Ω

3. Ignition ON, test for 4.8 - 5.2 V between the 5 V reference circuit terminal 1 and ground.

• If less than 4.8 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the 5 V reference circuit and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the 5 V reference circuit end to end.
   • If 2 Ω or greater, repair the open/high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

NOTE: If the signal circuit is shorted to a voltage the ECM or the MAP Sensor may be damaged.

• If greater than 5.2 V

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Ignition ON, test for less than 1 V between the 5 V reference circuit and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K20 Engine Control Module.

• Go to next step: If between 4.8 - 5.2 V

4. Ignition ON, verify the scan tool MAP Sensor parameter is less than 0.5 V.

• If 0.5 V or greater

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Ignition ON, test for less than 1 V between the signal circuit terminal 3 and ground.
   • If 1 V or greater, repair the short to voltage on the circuit.
   • If less than 1 V, replace the K20 Engine Control Module.

• Go to next step: If less than 0.5 V

5. Ignition OFF, install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 1.

6. Ignition ON, verify the scan tool MAP Sensor voltage parameter is greater than 4.5 V.

• If 4.5 V or less

1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Remove the jumper wire, test for infinite resistance between the signal circuit terminal 3 and ground.
   • If less than infinite resistance, repair the short to ground on the circuit.
   • Go to next step: If infinite resistance
3. Test for less than 2 Ω in the signal circuit end to end.
   • If 2 Ω or greater, repair the open or high resistance in the circuit.
   • If less than 2 Ω, replace the K20 Engine Control Module.

• Go to next step: If greater than 4.5 V

7. Test or replace the B74 Manifold Absolute Pressure Sensor.

Component Testing

NOTE: You must perform the Circuit/System Testing in order to verify the integrity of the MAP Sensor circuits before proceeding with the Component Testing.

Skewed Sensor Test

1. Ignition OFF, remove the B74 Manifold Absolute Pressure Sensor from the engine. Connect the harness to the sensor, if disconnected.

2. Ignition ON, apply 17 kPa (5.0 in Hg) of vacuum to the B74 Manifold Absolute Pressure Sensor, with the GE-23738-A. Verify the scan tool MAP pressure parameter decreases between 13 - 21 kPa (1.8 - 3.0 PSI).

• If the parameter does not decrease between 13 - 21 kPa (1.8 - 3.0 PSI)

Replace the B74 Manifold Absolute Pressure Sensor.

• Go to next step: If the parameter does decrease between 13 - 21 kPa (1.8 - 3.0 PSI)

3. Apply 34 kPa (10.0 in Hg) of vacuum to the B74 Manifold Absolute Pressure Sensor, with the GE-23738-A. Verify the scan tool MAP pressure parameter decreases between 30 - 38 kPa (4.4 - 5.5 PSI).

• If the parameter does not decrease between 30 - 38 kPa (4.4 - 5.5 PSI)

Replace the B74 Manifold Absolute Pressure Sensor.

• Go to next step: If the parameter does decrease between 30 - 38 kPa (4.4 - 5.5 PSI)

4. All OK.

Erratic Signal Test

1. Ignition OFF, remove the B74 Manifold Absolute Pressure Sensor and disconnect the harness.

2. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 1 of the sensor and the sensor harness.

3. Install a jumper wire between the low reference circuit terminal 2 of the sensor and ground.

4. Install a jumper wire to the signal circuit terminal 3 of the sensor.

5. Connect a DMM between the jumper wire and ground.

6. Ignition ON, observe the DC voltage on the DMM. Slowly apply between 0-15 kPa (0 - 4.4 in Hg) of vacuum to the sensor with the GE-23738-A Vacuum Pump. Verify the voltage changes, without any spikes or dropouts and is between 0.2 - 4.9 V.

• If not between 0.2 - 4.9 V or has spikes or dropouts
  • Replace the B74 Manifold Absolute Pressure Sensor.
• Go to next step: If between 0.2 - 4.9 V and there are no spikes or dropouts

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Manifold Absolute Pressure Sensor Replacement.
• Control Module References for engine control module replacement, programming, and setup

READ NEXT: