P0108

Diagnostic Charts:

Diagnostic Charts (cont'd):

Wiring Diagram:

CIRCUIT DESCRIPTION

The Manifold Absolute Pressure (MAP) sensor is mounted to the top of the intake manifold. The MAP sensor measures pressure changes within the intake manifold which are an indication of engine load. The MAP sensor has a 5.0 volt reference, a ground and a signal circuit.

The MAP sensor contains a diaphragm which changes resistance based on pressure. When manifold pressure is low (high vacuum) sensor output voltage is low. When manifold pressure is high (low vacuum) sensor output voltage is high.

MAP sensor voltage (depending on altitude) can range from 1.0-1.5 volts at idle (high vacuum) to 4.0-4.9 volts at wide open throttle (low vacuum). When the PCM senses a signal voltage higher than the normal operating range of the sensor, this DTC will set.

CONDITIONS FOR SETTING THE DTC

- DTCs P0122 and P0123 not set.

- Engine Operating.

- Throttle Position (TP) sensor angle less than 3% when RPM is greater than 1000 RPM.

- TP sensor angle 0% when engine speed is below 1000 RPM.

- MAP voltage is greater than 4.2 volts.

- All conditions met for 3 seconds.

ACTION TAKEN WHEN THE DTC SETS

- The PCM will illuminate the Malfunction Indicator Lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails.

- The PCM will record operating conditions at the time the diagnostic fails. The first time the diagnostic fails, this information will be stored in Failure Records. If the diagnostic reports a failure on the second consecutive drive trip, the operating conditions at the time of failure will be written to Freeze Frame and the Failure record will be updated.

- The PCM will use TP sensor values to calculate MAP.

CONDITIONS FOR CLEARING THE MIL/DTC

- The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail.

- A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.

- A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

- PCM battery voltage is interrupted.

- Using a Scan tool.

DIAGNOSTIC AIDS

- An intermittent may be caused by the following:

- Mis-routed harness.

- Rubbed through wire insulation.

- Broken wire inside the insulation.

- If other DTCs are set that share the same ground and/or 5.0 volt reference circuit, check for faulty connections and for faulty wiring.

- The PCM 5 volt reference circuits are internally connected within the PCM. If all the MAP sensor circuits check to be OK, inspect related 5.0 volt reference circuits.

- If it is determined that the DTC occurs intermittently, performing the DTC P1106 diagn9stic table may isolate the cause of the fault.

For intermittents, refer to Symptoms.

TEST DESCRIPTION

Number(s) below refer to step numbers on the diagnostic table.

2. Determines if the malfunction is present. For any test that requires back probing the PCM or component harness connectors, must use the Connector Test Adapter Kit J 35616-A. Using this kit will prevent any damage to the harness connector terminals.

3. Using Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If the DTC cannot be duplicated, the information included in the Freeze Frame and/or Failure Records data can be useful in determining how many miles since the DTC set. The Fail Counter and Pass Counter can also be used to determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that were noted. This will isolate when the DTC failed.

4. This checks whether the signal circuit is shorted to a voltage.

5. This checks whether a ground circuit is available at the MAP sensor.

8. Remove the MAP sensor and check if vacuum is available to the sensor. Also inspect MAP sensor seal for nicks and cuts. A vacuum leak at the seal will cause P0108 to set.