With Generic Scan Tool
Needle Lift Sensor, Checking
The needle lift sensor signal is used to determine the start of injection. If it fails the start of injection is activated (RPM and load dependent), during normal driving operation the start of injection is regulated (RPM, load and temperature dependent).
NOTE: When servicing terminals in the harness connector for the Needle Lift Sensor, use only gold-plated terminals.
Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram
Test requirement
- The respective fuses of Diesel-Direct fuel injection system must be OK.
- Battery voltage must be at least 11.5 Volts.
Test sequence
- Disconnect 2-pin harness connector for needle lift sensor (arrow).
- Measure resistance between sensor terminals.
Specified value: 80...120 Ohm
If specified value is not obtained:
- Replace cylinder 3 injector with Needle Lift Sensor -G80-, item no. 7. Procedures
- Erase DTC memory of control module for Diesel-Direct fuel injection system, Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specified value is obtained:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
Vehicles with 80-pin control module
- Check for open circuit in wires between test box and connector according to wiring diagram.
Terminal 1 + socket 62
Terminal 2 + socket 55
Wire resistance: max. 1.5 Ohm
Vehicles with 121-pin control module
- Check for open circuit in wires between test box and connector according to wiring diagram.
Terminal 1 + socket 109
Terminal 2 + socket 101
Wire resistance: max. 1.5 Ohm
Continuation for all vehicles
- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinite Ohm
If no malfunctions are detected in wires:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes