With Manufacturer's Scan Tool
Modulating Piston Displacement Sensor and Quantity Adjuster, Checking
The quantity adjuster -N146- is an electromagnetic swivel type positioner, controlled by the ECM via regulated duty cycle (ON-OFF ratio). The eccentric shaft on -N146- moves the modulating piston on the high pressure piston thereby regulating the quantity of fuel injected.
The modulating piston displacement sensor -G149- communicates the position of -N146- to the ECM thereby determining the quantity of fuel to be injected.
Special tools and workshop equipment required
- VAG 1551/1552 Scan Tool using VAG 1551/3 Adapter cable
- VAG 1598/22 test box (MY 1999)
- VAG 1598/31 test box (from MY 2000)
- Fluke 83 multimeter
- VW 1594 Adapter kit
- Wiring diagram
Test sequence
- Connect VAG 1551/1552 Scan Tool.
- Start engine and let idle.
- Press 0 and 1 buttons to select Address word 01: "Engine electronics"
Display will appear as shown (example only)
038906018M 1.9l R4 EDC 00AG 1813 ->
Coding 0001 WSC XXXXX
- Press -> button.
Display will appear as shown
Rapid data transfer HELP
Select function XX
- Press 0 and 8 buttons to select Function 08: "Read measuring value block".
- Press Q button to enter input.
Display will appear as shown
Read measuring value block HELP
Input Display group number XXX
- Press buttons 0, 0 and 1 to select "Display group 1".
- Press Q button to enter input.
Read measuring value block 1 ->
840 rpm 6.5 mg/H 1.480 V 87.3 °C
Display will appear as shown
- Check engine coolant temperature value in display zone 4.
- Specification: 85°C minimum
- Continue with check only when temperature spec. is attained.
- Check value in display zone 3 (Voltage from modulating piston movement).
Read measuring value block 1 ->
840 rpm 6.5 mg/H 1.480 V 87.3 °C
- Check modulating piston displacement sensor -G149- Voltage supply value in display zone 3.
Specification: 1.450 to 2.000 Volts
If specification not obtained.
- Check modulating piston displacement sensor -G149- and quantity adjuster as described in following:
Modulating piston displacement sensor, checking
- Press -> button.
Display will appear as shown
Rapid data transfer HELP
Select function XX
- Press 0 and 6 buttons to select Function 06: "End output".
- Press Q button to enter input.
- Switch OFF ignition.
- Disconnect 10-pin fuel temperature sensor harness connector (connection to Diesel injection pump metering control).
- Switch Fluke 83 multimeter to resistance range
- Measure resistance between connector terminals: 1 + 2 and 2 + 3.
Specification: 4.9 to 7.5 Ohms
If specification not obtained
- Replace diesel injection pump.
- Display the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory was erased
- Set the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specification obtained
- Connect -VAG1598/22- (or -1598/31-) test box to ECM wiring harness.
- Check wiring for open circuit between test box and harness connector using Wiring diagram.
Up to MY 1999
- Terminal 1 + socket 56
- Terminal 2 + socket 57
- Terminal 3 + socket 64
From MY 2000
- Terminal 1 + socket 108
- Terminal 2 + socket 106
- Terminal 3 + socket 99
Wire resistance: 1.5 Ohms maximum
- Check wires for shorting to: one another, Ground and Battery +
Specification: Infinity Ohms
If wiring OK
- Replace engine control Module -J248-
- Display the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory was erased
- Set the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
Quantity adjuster -N146-, checking
- Press -> button.
Display will appear as shown
Rapid data transfer HELP
Select function XX
- Press 0 and 6 buttons to select Function 06: "End output".
- Press Q button to enter input.
- Switch OFF ignition.
- Disconnect 10-pin fuel temperature sensor harness connector (connection to diesel injection pump metering control).
- Measure resistance between connector terminals 5 + 6.
Specification: 0.5 to 2.5 Ohms
If specification not obtained
- Replace diesel injection pump.
- Display the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory was erased
- Set the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specification obtained
- Connect -VAG1598/22- (or -1598/31-) test box to ECM wiring harness.
- Check wiring for open circuit between test box and harness connector using Wiring diagram.
Up to MY 1999
- Terminal 5 + sockets 2 and 28
- Terminal 6 + sockets 59, 66 and 80
From MY 2000
- Terminal 5 + sockets 1 and 2
- Terminal 6 + sockets 116 and 121
Wire resistance: 1.5 Q maximum
- Check wires for shorting to: one another, Ground and Battery +.
Specification Infinity Ohms
If wiring OK
- Replace engine control module - J248-
- Display the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If DTC memory was erased
- Set the readiness code. Monitors, Trips, Drive Cycles and Readiness Codes