For 1990-2009 cars
Engine Controls Components
Cell 20: Sensors
OBD II Symbol Description Notice

### Circuit Description

VIN K

The Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure. The PCM supplies a 5 volt reference and a ground for the MAP sensor. The MAP sensor provides a signal to the PCM relative to pressure changes in the manifold. The MAP sensor signal voltage to the PCM varies from below 2 volts at idle (low manifold absolute pressure - high vacuum) to above 4 volts with the key ON, engine not running or at wide-open throttle (high manifold absolute pressure - low vacuum). 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 be set.

VIN 1

The Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure. The PCM supplies a 5 volt reference and a ground for the MAP sensor. The MAP sensor circuit provides a signal to the PCM relative to pressure changes in the manifold. With the key ON, engine not running, the MAP sensor signal voltage to the PCM varies between 1.5 to 2.5 volts. With the engine running, the MAP sensor voltage to the PCM varies from below 2 volts at idle (low manifold absolute pressure - high vacuum) to above 4 volts at wide-open throttle (high manifold absolute pressure - low vacuum). 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 be set.

### Conditions for Setting the DTC

• | No TP sensor DTCs present.

• | 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 less than 2%.

• | Engine speed is less than 900 RPM.

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

• | The above conditions are present for at least 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 and Failure Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been 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 the scan tool.

### Diagnostic Aids

Check for the following conditions:

• | Poor connection at the PCM.

| Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

• | Damaged harness.

| Inspect the wiring harness for damage. If the harness appears to be OK, observe the MAP display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the malfunction.

If DTC P0108 cannot be duplicated, the information included in the Fail Records data can be useful in determining since the DTC was last set. If it is determined that the DTC occurs intermittently, performing the DTC P1108 Diagnostic Table may isolate the cause of the malfunction.

### Test Description

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 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | 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 .
2. With the engine idling, observe the MAP value on the scan tool.

Is the MAP voltage greater than the specified value?

3.5V

Go to Step 4

Go to Step 3

3 |

1. Turn ON the ignition switch.
2. Review and record scan tool Fail Records data.
3. Operate the vehicle within Fail 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. Disconnect the MAP sensor electrical connector.
2. Observe the MAP sensor voltage displayed on the scan tool.

Is the MAP sensor voltage at the specified value?

0V

Go to Step 5

Go to Step 6

5 | Probe the MAP sensor ground circuit with a test lamp to B+. Is the test lamp ON? | -- | Go to Step 7 | Go to Step 9
6 |

1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Turn ON the ignition switch.
4. Check the MAP signal circuit for a short to voltage or a short to the 5 volt reference A circuit.
5. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was the MAP sensor signal circuit shorted?

--

Go to Step 16

Go to Step 11

7 |

1. Check for poor MAP sensor ground circuit terminal connection at the MAP sensor electrical connector.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 16

Go to Step 8

8 | Check for a plugged or leaking vacuum supply to the MAP sensor. Was a problem found? | -- | Go to Step 15 | Go to Step 12
9 |

1. Check for a poor MAP sensor ground circuit terminal connection at the PCM.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 16

Go to Step 10

10 |

1. Check for an open in the MAP sensor ground circuit.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 16

Go to Step 1

11 | Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is action complete? | -- | Go to Step 16 | --
12 |

1. Turn OFF the ignition switch.
2. Disconnect the PCM.
3. Turn ON the ignition switch.
4. Check for a short to voltage on the 5 volt reference A circuit.
5. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 16

Go to Step 13

13 |

1. Check for poor electrical connections at the MAP sensor.
2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a problem found?

--

Go to Step 16

Go to Step 14

14 | Replace the MAP sensor. Refer to one of the following procedures:

• | Manifold Absolute Pressure Sensor Replacement

• | Manifold Absolute Pressure Sensor Replacement

Is action complete?

--

Go to Step 16

--

15 | Repair the malfunctioning vacuum source. Is action complete? | -- | Go to Step 16 | --
16 |

1. Turn ON the ignition switch.
2. Review and record scan tool Fail Records data.
3. Clear DTCs.
4. Operate the vehicle within Fail Records conditions.
5. Using a scan tool, monitor Specific DTC info for DTC P0108.

Does the scan tool indicate DTC P0108 failed?

--

Go to Step 4

System OK