For 1990-2009 cars
Engine Controls Components
Engine Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The manifold absolute pressure (MAP) sensor responds to changes in intake manifold pressure (vacuum). The MAP sensor signal voltage to the PCM varies from below 2-volts at idle (high vacuum) to above 4 volts with the key ON, engine not running or at wide-open throttle (low vacuum). The MAP sensor is used to determine manifold pressure changes while the EGR flow test diagnostic is being run, refer to DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient . Also to update the barometric pressure reading (BARO), as an enabling factor for other diagnostics. The PCM monitors the MAP signals for voltages outside the normal range of the MAP sensor. If the PCM detects a MAP signal voltage that is excessively high, DTC P0108 will set.

### Conditions for Running the DTC

• | TP sensor DTCs are not present.

• | System voltage is more than 9.0 volts.

• | Engine has been running for a length of time that is determined by startup coolant temperature. The length of time ranges from 2 minutes at less than -30°C (-22°F) to 0.5 second at more than 30°C (86°F).

• | Throttle position is below 2 percent if the engine speed is less than 3000 RPM

• | Throttle position is above 30 percent if the engine speed is more than 3000 RPM.

### Conditions for Setting the DTC

• | The MAP sensor signal voltage is more than 4.2 volts.

• | The above condition is present for longer than 200 3X reference periods (67 crankshaft revolutions).

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.

• | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed.

• | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using a scan tool.

### Diagnostic Aids

Inspect for the following conditions:

Many situations may lead to an intermittent condition. Perform each inspection or test as directed.

Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

• | Loose terminal connection

- | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.

- | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair.

• | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

• | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair.

If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.

### Test Description

The numbers below refer to the step numbers on the diagnostic table:

1. This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read only memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

#### DTC P0108 - MAP Sensor Circuit High Voltage

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 |

1. If the engine idle is rough, unstable or incorrect, repair the idle problem before continuing with this table. Refer to Rough, Unstable, or Incorrect Idle and Stalling in Symptoms.
2. With the engine idling, observe the MAP voltage parameter on a scan tool.

Does the scan tool indicate that the MAP voltage parameter is more than the specified value?

4.2 V

Go to Step 4

Go to Step 3

3 |

1. Turn ON the ignition, with the engine OFF.
2. Review and record scan tool Failure Records data.
3. Operate the vehicle within Failure Records conditions.
4. Using a scan tool, monitor Specific DTC info for DTC P0108.

Does the scan tool indicate DTC P0108 failed?

--

Go to Step 4

Go to Diagnostic Aids

4 |

1. Turn OFF the ignition.
2. Disconnect the MAP sensor.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool, observe the MAP voltage parameter.

Does the scan tool indicate that the MAP voltage parameter is at the specified value?

0 V

Go to Step 5

Go to Step 7

5 | Test for a plugged or leaking vacuum supply to the MAP sensor. Did you find and correct the condition? |  | Go to Step 12 | Go to Step 6
6 | Test the ground circuit of the MAP sensor for continuity. Refer to Testing for Continuity in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 8
7 | Test the signal circuit of the MAP sensor for a short to voltage or short to 5-Volt Reference A circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 11
8 | Inspect the ground circuit of the MAP sensor at the PCM for a poor connection at the harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9
9 | Inspect the ground circuit of the MAP sensor at the MAP sensor for poor connections at the harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 10
10 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | --
11 | Important:: The replacement PCM must be reprogrammed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Step 12 | --
12 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 4

System OK