P0108

DTC P0108

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, and barometric pressure (BARO). 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-volt 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 highest pressure that can exist in the intake manifold is equal to BARO. This occurs when the vehicle is operated at wide-open throttle (WOT) or when the ignition is on while the engine is off. Under these conditions, the ECM uses the MAP sensor to determine the current BARO. The lowest manifold pressures occur when the vehicle is idling or decelerating. MAP can range from 10 kPa, when pressures are low, to as much as 104 kPa when pressures are high, depending on the BARO. The ECM monitors the MAP sensor signal for pressure outside of the normal range. If the ECM detects that the MAP sensor pressure is excessively high, DTC P0108 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

CONDITIONS FOR RUNNING THE DTC
- DTCs P0641, P0651, P1516, P1680, P1681, P2101, P2120, P2125, P2135, P2138, P2176 are not set.
- The engine has been running for a period of time that is determined by the start-up coolant temperature. The time ranges from 8 seconds at less than -30°C (-22°F) to 3 seconds at more than 30°C (86°F).
- The throttle angle is less than 2.2 percent when the engine speed is less than 1,100 RPM.OR
- The throttle angle is less than 4.5 percent when the engine speed is more than 1,100 RPM.
- This DTC runs continuously within the enabling conditions.

CONDITIONS FOR SETTING THE DTC
The ECM detects that the MAP sensor pressure is more than 102 kPa for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-10:

Steps 11-16:

The number below refers to the step number on the diagnostic table.
8. This step tests the ground path, from the sensor through the controller, for an open or excessive resistance.