Needle Lift Sensor, Checking
The needle lift sensor signal determines the start of injection during normal operation by closed-loop control based on RPM, load and temperature. If the sensor malfunctions, control switches to open-loop, based on RPM and load.
The Needle Lift Sensor -G80- is part of the cylinder 3 Fuel Injector -- and cannot be serviced separately.
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- fuses OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- 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
-- Disconnect the Needle Lift Sensor -G80- electrical harness connector -1-.
Checking internal resistance
-- Using a multimeter, check the Needle Lift Sensor -G80- terminals 1 to 2 for resistance.
Specified value: 80 to 120 Ω
If the specified value was not obtained:
-- Replace cylinder 3 Fuel Injector --. Refer to Diesel Fuel Injection .
If the specified value was obtained:
Checking wiring
If the manufacturers test box is being used, perform the following step.
-- Install the test box. Refer to 68 PIN TEST BOX ADAPTER, INSTALLING .
If the manufacturers test box is not being used, perform the following step.
-- Remove the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-. Refer to ENGINE CONTROL MODULE, REPLACING .
-- Using a Multimeter --, check the Needle Lift Sensor -G80- electrical harness connector terminals to the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- electrical harness connector T80 terminals for resistance.
| Needle Lift Sensor -G80- electrical harness connector terminals | Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- electrical harness connector T80 terminals or test box socket |
|---|---|
| 1 | 62 |
| 2 | 55 |
Specified value: 1.5 Ω Max.
If the specification was not obtained:
-- Check the wiring for a 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:
-- 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:
Repair complete, Generate readiness code. Refer to READINESS CODE .
-- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was not OK:
-- Replace the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-. Refer to ENGINE CONTROL MODULE, REPLACING .
-- Assembly is performed in the reverse of the removal.
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 .
End of diagnosis