P0108

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The Manifold Absolute Pressure (MAP) sensor responds to changes in intake manifold pressure. The MAP sensor signal voltage to the Powertrain Control Module (PCM) varies from less than 2 volts at idle, or high vacuum, to more than 4 volts with the key ON, and the engine is 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, and also to update the Barometric Pressure Reading (BARO), as an enabling factor for other diagnostics. Refer to DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient. 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. P0401

CONDITIONS FOR RUNNING THE DTC
^ No Throttle Position (TP) sensor DTCs are present.
^ The system voltage is more than 9.0 volts.
^ The engine has been running for a length of time that is determined by the start-up coolant temperature. The length of time ranges from 2 minutes at less than -30°C (-22°F) to 1 second at more than 30°C (86°F).
^ The throttle position is below 2 percent, if the engine speed is less than 3000 RPM.
^ The throttle position is below 30 percent if engine speed is above 3000 RPM.

CONDITIONS FOR SETTING THE DTC
^ The MAP sensor signal voltage is more than 4.3 volts.
^ The above conditions are 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 and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.

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 a scan tool.

DIAGNOSTIC AIDS
Inspect for the following conditions:

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.

^ Faulty terminal connection
Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Diagrams.
^ A 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 Diagrams.
^ Inspect the PCM and the engine grounds for clean and secure connections.

If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.

TEST DESCRIPTION
The numbers below refer to the step numbers on the Diagnostic Table:
11. 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.