P0108

Diagnostic Chart:

Wiring Diagram:

Circuit Description

The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure (vacuum). The Powertrain Control Module (PCM) provides a 5 volt reference voltage to the MAP sensor. The change in the pressure, that results from engine load and RPM changes, is converted into a voltage input that is monitored by the PCM. A low voltage reading at the PCM indicates low manifold pressure, and a high voltage reading at the PCM indicates high manifold pressure.

Conditions for Setting the DTC

^ High voltage input at the PCM indicating manifold absolute pressure above 130 kPa or higher.

^ The above condition is met for at least 0.5 seconds.

Action Taken When the DTC Sets

^ The Malfunction Indicator Lamp (MIL) will illuminate.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.

^ The PCM will enter the Fail-Safe Function and rely on Throttle Position (TP) sensor and engine RPM while stopping EGR and EVAP purge control.

Conditions for Clearing the MIL/DTC

^ The MIL will turn OFF after three consecutively passing cycles without a fault present.

^ A History DTC will clear after 40 consecutive warm-up cycles without a fault.

^ DTCs can be cleared by using a scan tool or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for any of the following conditions:

^ Check for a leaking hose to the MAP sensor.

^ Check for engine vacuum leaks.

^ A poor connection at PCM. Inspect the wiring harness connectors for backed out terminal, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.

^ A damaged wiring 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 MAP sensor. A change in the MAP display will indicate the location of the fault.

^ If a DTC P0108, P0113, P0118, and P0123 are set together the cause could be an open ground circuit (LT. GRN/BLK wire).

^ For additional information on the MAP sensor refer to MAP Sensor / Description and Operation.

^ It may be possible for the 5 volt reference circuit to be shorted to voltage and set a DTC P0108.

If a DTC P010B cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

If any wiring repairs need to be made, Refer to Repair Procedures in Electrical Diagrams.

Test Description

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Determines if fault is present.

3. Review Freeze Frame data to determine when the DTC set. Always record this information.

7. Checks the ground circuit for a open.