Charge Air Pressure Sensor, Checking
Use only gold-plated terminals when servicing terminals in harness connector of Charge Air Pressure Sensor -G31-.
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The Motronic Engine Control Module (ECM) - J623- fuses OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- On vehicles with automatic transmission, selector lever in position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.
Test procedure
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .
Start diagnosis
-- Remove the engine cover with air filter.
Test sequence
-- Disconnect the Charge Air Pressure Sensor -G31- electrical harness connector -arrow-.
-- Start engine and let it run at idle.
-- Using a multimeter, check the Charge Air Pressure Sensor -G31- electrical harness connector terminals 1 to 3 for voltage.
Specified value: min. 4.5 V
-- Switch the ignition off.
If the specification was not obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
-- Install the Test Box 105 Pin VAG 1598/42.
If the manufacturers test box is not being used. Perform the following step.
-- Remove the Motronic Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, REMOVING AND INSTALLING .
-- Using a multimeter, check the Charge Air Pressure Sensor -G31- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T94 terminals for resistance.
| Charge Air Pressure Sensor -G31- electrical harness connector terminals | Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminals or test box sockets |
|---|---|
| 1 | 53 |
| 3 | 19 |
| 4 | 38 |
Specified value: 1.5 Ω max.
If the specification was not obtained:
-- Check the wiring for an open circuit, short circuit to each other, Battery (+), and Ground (GND).
-- If necessary, repair the faulty wiring connection.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
If no malfunction is detected in the wiring and if the voltage supply was OK:
-- Replace the Charge Air Pressure Sensor -G31- Refer to Throttle Valve Control Module -J338- .
If no malfunction is detected in the wiring and if the voltage supply was not OK:
-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to ENGINE CONTROL MODULE, REMOVING AND INSTALLING .
-- Install the engine cover with air filter.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .