P0108-Manifold Absolute Pressure sensor circuit high
July 22, 2017
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P0108 code - the Manifold Absolute Pressure (MAP) sensor is a transducer that varies resistance according to pressure changes in the Intake Manifold. The MAP sensor signal provides the Powertrain Control Module (PCM) with an indication of the current air pressure within the Intake Manifold. The PCM uses this information to help calculate fuel delivery.
The MAP sensor functions as typical three wire sensor. The PCM supplies 5 Volts to the MAP sensor on a 5 volt reference circuit and provides a ground on a low reference circuit. The MAP sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes. The PCM receives the Barometric Pressure (BARO) sensor reading from the MAP sensor with the ignition on, before the engine is cranking or running. Set conditions the powertrain Control Module (PCM) detects that the Manifold Absolute Pressure (MAP) sensor input voltage is above the maximum acceptable value. Default actions ETC Light will illuminate, the MIL Light will illuminate.
When monitored P0108 code:
Possible causes P0108 code:
Step 2. Check the 5 Volt supply circuit for a short to voltage
Step 3. Check the MAP signal circuit for a short to voltage
Step 4. Check for the MAP Signal circuit shorted to the 5 volt supply circuit
Step 6. Check the sensor ground circuit for an open/high resistance
Step 7. MAP Sensor
The MAP sensor functions as typical three wire sensor. The PCM supplies 5 Volts to the MAP sensor on a 5 volt reference circuit and provides a ground on a low reference circuit. The MAP sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes. The PCM receives the Barometric Pressure (BARO) sensor reading from the MAP sensor with the ignition on, before the engine is cranking or running. Set conditions the powertrain Control Module (PCM) detects that the Manifold Absolute Pressure (MAP) sensor input voltage is above the maximum acceptable value. Default actions ETC Light will illuminate, the MIL Light will illuminate.
- With the ignition on.
- Battery voltage greater than 10.4 volts.
Possible causes P0108 code:
- 5 Volt supply circuit shorted to voltage.
- MAP Signal circuit shorted to voltage.
- MAP Signal circuit shorted to the 5 Volt supply circuit.
- MAP Signal circuit open/high resistance.
- Sensor ground circuit open/high resistance.
- MAP Sensor.
- Powertrain Control Module (PCM).
Diagnose code P0108-Manifold absolute pressure sensor circuit high
Step 1. Check for an active DTC
Turn the ignition on, with the scan tool, read DTC.
Is the DTC active or pending ?
Yes, go to step 2.
No, perform the PCM intermittent condition.
Step 2. Check the 5 Volt supply circuit for a short to voltage
Disconnect the MAP sensor harness connector. Measure the voltage on the 5 Volt supply circuit at the MAP sensor harness connector.
Is the voltage above 5.2 volts ?
Yes, repair the 5 Volt supply circuit for a short to voltage.
No, go to step 3.
Step 3. Check the MAP signal circuit for a short to voltage
Measure the voltage on the MAP Signal circuit at the MAP Sensor harness connector.
Is the voltage above 5.2 Volts?
Yes, repair the MAP Signal circuit for a short to voltage.
No, go to step 4.
Step 4. Check for the MAP Signal circuit shorted to the 5 volt supply circuit
Turn the ignition off, disconnect the PCM Harness connector. Check for continuity between the MAP Signal circuit and the 5 Volt supply at the MAP Sensor harness connector.
Is there continuity between the MAP Signal circuit and the 5 Volt supply?
Yes, repair the MAP Signal circuit for a short to the 5 Volt supply circuit.
No, go to step 5.
Step 5. Check the MAP Signal circuit for an open/high resistance
Step 5. Check the MAP Signal circuit for an open/high resistance
Measure the resistance on the MAP Signal between the MAP Sensor harness connector and the PCM Harness connector.
Is the resistance below 3.0 Ohms?
Yes, go to step 6.
No, repair the MAP Signal for an open or high resistance.
Step 6. Check the sensor ground circuit for an open/high resistance
Measure the resistance of the Sensor ground circuit between the MAP sensor harness connector and the PCM Harness connector.
Is the resistance below 3.0 Ohms?
Yes, go to step 7.
No, repair the Sensor ground circuit for an open/high resistance.
Step 7. MAP Sensor
Reconnect the PCM harness connector, connect a jumper between the Sensor Ground circuit and the MAP Signal circuit at the MAP Sensor harness connector. Turn the ignition on, with the scan tool, read DTC.
Note : The scan tool should display a '' P0107-Manifold Absolute Pressure sensor circuit low'' DTC as active or pending with the jumper place.
Does the scan tool display the DTC as described above?
Yes, replace the MAP Sensor.
No, go to step 8.
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