DTC 00765
DTC code: 00765:Modulating Piston Displacement Sensor G149
The Modulating Piston Displacement sensor informs the ECM of the Quantity Adjuster position and stipulates the amount injected.
Special Tools, Testers And Auxiliary Items:
- VAG 1598/18 Test Box adaptor
- Fluke 83 Multimeter or equivalent
- VW 1594 Adaptor kit
- Wiring diagram
Work Sequence:
Display will appear as shown:
Rapid data transfer HELP
Select function XX
- Press C 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 XX
- Press buttons 0 and 1 to select "display group 01"
- Press Q button to enter input
- Observe Engine Coolant Temperature (ECT) in channel 4
Display will appear as shown:
Read measuring value block 1 -->
840 rpm 6.5 mg/H 1.480 V 87.3°C
Specification: at least 85°C
- Continue with check when specified ECT is obtained
Display will appear as shown:
Read measuring value block 1 -->
840 rpm 6.5 mg/H 1.480 V 87.3°C
- Observe voltage display from Modulating Piston Displacement sensor G149 in channel 3:
Specification: 1.250 to 1.750 Volts
If specified voltage not obtained:
- Press -> button
- Press 0 and 6 buttons to select Function 06 "End data transfer"
- Press Q button to enter input
- Switch OFF ignition
- Disconnect Fuel Temperature sensor G81 harness connector (for connection to Quantity Adjuster N146)
- Measure resistance between connector terminals 1 + 2, 2 + 3:
Specification: 5 to 7 ohm
If specified resistance not obtained:
- Replace injection pump
If specified resistance obtained:
- Connect VAG 1598/18 Test Box adaptor to ECM wiring harness connector -1-
- Check wiring for open circuit between VAG 1598/18 Test Box adaptor and harness connector using wiring diagram:
Terminal 1 + socket 29
Terminal 2 + socket 7
Terminal 3 + socket 52
Wire resistance: 1.5 ohms maximum
- Check for shorting between wires
Specification: infinite ohm
If no malfunction detected:
- Replace ECM J248