Charge Air Pressure Sensor, Checking
Observe all safety precautions: SAFETY PRECAUTIONS
View clean working conditions: CLEAN WORKING CONDITIONS
Prior to repair work, perform a preliminary check to verify the condition. Refer to PRELIMINARY CHECK .
The Charge Air Pressure Sensor and IAT Sensor are combined and must be replaced as a unit.
Use only gold-plated terminals when servicing terminals in the electrical harness connector of the Charge Air Pressure Sensor/IAT sensor -G31/G42-.
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 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. Refer to the Repair information.
Test sequence
-- Disconnect the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector.
-- Turn ON the ignition switch.
-- Using a multimeter, check the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals 1 to 3 for voltage.
Specified value: Near 5 V
-- Using a multimeter, check the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals 1 to 4 for voltage.
Specified value: Min. 4.40 V
-- Switch the ignition off.
If either specified value was Not obtained:
Checking wiring
If the manufacturers test box is being used, perform the following step.
-- Install the test box.
If the manufacturers test box is not being used, perform the following step.
-- Remove the Motronic Engine Control Module (ECM) -J623-. Refer to the Repair information.
-- Using a multimeter, check the Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for an open circuit according to wiring diagram.
| Charge Air Pressure Sensor/IAT sensor -G31/G42- electrical harness connector terminals | Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminals or test box sockets |
|---|---|
| 1 | 66 |
| 2 | 30 |
| 3 | 17 |
| 4 | 83 |
Specified value: 1.5 Ω max.
If the specified value was Not obtained:
-- Check the wiring for an open, high resistance or short to ground.
-- 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 the voltage supply was OK:
-- Replace the Charge Air Pressure Sensor/IAT sensor -G31/G42- Refer to the Repair information.
If no malfunction is detected in the wiring and the voltage supply was Not OK:
-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to the Repair information.
-- Install the engine cover. Refer to the Repair information.
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 .