P0108
DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage
Circuit Description
The manifold absolute pressure (MAP) sensor is mounted in front of the intake manifold. The MAP sensor measures pressure changes within the intake manifold, which is an indication of engine load. The MAP sensor has a 5.0 volt reference, a ground and a signal circuit. The MAP sensor contains 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.
Conditions for Running the DTC
* No TP sensor DTCs are set.
* The engine is running.
* TP sensor is more than 0 percent when engine speed is less than 600 RPM.
* TP sensor is more than 20 percent when engine speed is more than 600 RPM.
Conditions for Setting the DTC
* The ignition voltage is between 10 and 11 volts.
* The MAP voltage is more than 4.34 volts for more than 1 second.
Action Taken When the DTC Sets
* The PCM turns on 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
Important: If the last failure was during a non-typical driving condition, the MIL may remain ON longer than 3 drive trips. Review Freeze Frame and Failure Records for the last failure conditions.
* The PCM turns the MIL OFF after 3 consecutive drive trips when the test has Run and Passed and not Failed.
* A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant temperature exceeds 70°C (160°F) during the same ignition cycle.
* Use the scan tool Clear Information function.
* A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.
* Disconnect the PCM battery feed for 30 seconds.
Diagnostic Aids
* An intermittent ground in the MAP signal or the 5 volt reference circuit results in a DTC P1106.
* With the ignition ON and the engine OFF, the manifold pressure is equal to atmospheric pressure with the signal voltage high. The PCM uses this information as an indication of the vehicle's altitude. Comparison of this reading with a known good vehicle using the same sensor is a good way to check accuracy of a suspect sensor. Readings should be the same ±0.4 volts.
* An intermittent open in the MAP sensor signal circuit or the 5 volt reference circuit will result in a DTC P1107.
* The PCM 5 volt reference circuits are internally connected within the PCM. If all the MAP sensor circuits check to be OK, inspect all PCM 5 volt reference component/circuits for a malfunction.
Important: The electrical connector must remain securely fastened.
* Inspect the electrical connector.
Important: After removing the MAP sensor from the intake manifold, replace the MAP sensor to intake manifold seal.
* Remove the MAP sensor. Twist sensor by hand (only) to check for intermittent connections. Output changes more than 0.1 volt indicates a bad connector or connection. If OK, replace sensor. Refer to Manifold Absolute Pressure Sensor Replacement Service and Repair.
* For further diagnostic aids, refer to Symptoms Symptoms.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the malfunction is present.
3. Using the Freeze Frame and Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and a fail. Operate the vehicle within the same Freeze Frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed. For any test that requires probing the PCM or component harness connectors, use the connector test adapter kit. Using this kit prevents any damage to the harness connector terminals.
4. This step checks whether the signal circuit is shorted to a voltage.
5. This step checks whether a ground circuit is available at the MAP sensor. For any test that requires probing the PCM or component harness connectors, use the connector test adapter kit. Using this kit will prevent any damage to the harness connector terminals.
8. Remove the MAP sensor and check if vacuum is available to the sensor. Also, inspect the MAP sensor seal for nicks and cuts.
