P0105
DIAGNOSTIC TROUBLE CODES PO105, PO106, PO107, PO108Manifold absolute pressure sensor, malfunctioning or not working at all
Fault Symptom.
CHECK ENGINE lamp (MIL) on. Poor driveablity. Only basic charging pressure. Any other diagnostic trouble codes (oxygen sensor, adaptation). A/C compressor not working.
Conditions.
- If there is a short circuit/open circuit, a DTC will be generated after 2 seconds.
- In the event of an implausible pressure reading, a DTC will be generated after 2 minutes.
- If the hose has come loose, a DTC will be generated when fuel shut-off occurs in connection with engine braking.
DIAGNOSTIC PROCEDURE
1. Checking the vacuum hose--Inspect the vacuum hose between the pressure sensor and the intake manifold.
If the vacuum hose is OK, continue with point 2.
If the vacuum hose is not OK, change the vacuum hose.
2. Checking the pressure sensor's electrical interfaces--Turn the ignition switch to the ON position and then back to the OFF position.
Unplug the pressure. sensor's 3-pin connector.
Take voltage readings at the connector across:
- Pin 3 and battery negative about 5 V
- Pin 2 and battery negative about 5 V
- Battery positive and pin 1 about 12 V.
Check the control module's pressure sensor input for continuity.
Connect a Scan Tool.
Select "READ FUNCTIONS".
Select "INTAKE PRESSURE".
The Scan Tool should show a reading of 255 kPa.
Connect a jumper lead across pins 2 and 1 of the pressure sensor connector.
The Scan Tool should show a reading of 0 kPa.
The above tests show whether the control module and wiring as far as the pressure sensor are in good working order.
If all test readings are OK, change the pressure sensor.
If any test reading is not OK, continue with point 3.
3. Checking the Wiring Harness
Check The Wiring between the control module and the pressure sensor's 3-pin connector for continuity.
Check The Wiring for continuity, shorting and and stray currents.
If the readings are OK, continue with point 4.
If any reading is not OK, rectify the fault.
4. Final Check
Clear the diagnostic trouble code, drive the car on test and check whether the trouble code is generated afresh.
If the DTC is generated again, refer to Before Replacing A Control Module.
If the DTC is not generated again, the action taken to rectify the fault was correct, otherwise the fault is of intermittent nature.