Fuel Pressure Sensor, Checking
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- Fuel Pump (FP) Control Module -J538- OK.
- The fuses for the engine electronics OK.
- The fuel filter OK.
- The parking brake engaged.
- The battery voltage at least 12.5 V.
- The selector lever of automatic transmission in position "P" or "N".
- All electrical consumers switched off (radiator fan must NOT run during test).
- A/C switched off.
- The fuel tank at least 1 /4 filled.
- The ignition switched off.
Test procedure
-- Observe safety precautions. Refer to SAFETY PRECAUTIONS
-- Observe Clean Working Conditions. Refer to CLEAN WORKING CONDITIONS
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .
Start diagnosis
Procedure
Checking voltage
-- Disconnect the electrical harness connector -3- for the Fuel Pressure Sensor -G247-.
-- Switch the ignition on.
-- Using a multimeter check the Fuel Pressure Sensor -G247- electrical harness connector for voltage.
| Fuel Pressure Sensor -G247- electrical harness connector terminals | To test point: | Specification: |
|---|---|---|
| 1 | Battery positive | Battery voltage |
| 2 | Ground | Battery voltage |
| 3 | Ground | Near 5 V |
-- Switch the ignition off.
If specified value is obtained:
-- Replace the Fuel Pressure Sensor -G247-. Refer to the Repair information.
If the specified value was not obtained:
Checking wiring connections
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 the a multimeter check the following wiring connection for an open circuit.
| fuel Pressure Sensor -G247- electrical harness connector terminals | Motronic Engine Control Module (ECM) -J623- electrical connector T60 terminals or test box sockets |
|---|---|
| 1 | 37 |
| 2 | 25 |
| 3 | 23 |
Specified resistance 1.5 Ω max.
If the specification is not obtained:
-- Check the wiring for an open, high resistance or short circuit to voltage or ground.
-- If necessary, repair the wiring connection.
-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
-- Perform a road test to verify repair.
If the DTC does not return:
Generate readiness code. Refer to READINESS CODE .
If the DTC does return, no malfunction is detected in the wiring and the voltage supply is OK:
-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to the Repair information.
-- Assembly is performed in the reverse of the removal.
Final procedures
After repair work, the following work steps must be performed in the mentioned 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 .