Checking Modulating Piston Displacement Sensor G149

Fig 1: Fuel Injection Pump

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• Disconnect 10-pin connector from Modulating Piston Displacement Sensor G149 (connector to injection pump quantity adjuster) - arrow  -.

Fig 2: 10-Pin Connector & Terminals

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• Measure resistance between connector terminals 1 + 2 and 2 + 3.

• Specification: 4.9 to 7.5 Ω

If specification is not obtained:

• Replace injection pump → Injection pump, removing and installing  .
• Check DTC memory and, if necessary, repair any malfunctions and then erase → Diagnostic Trouble Code (DTC) memory, checking and erasing  .
• Read readiness code → Readiness code, displaying  .

If DTC memory has been erased, the readiness code must be generated again → Readiness code, setting  .

If specification is obtained:

• Remove wiper arms and plenum cover. →92 WINDSHIELD WIPER & WASHER SYSTEM

Fig 3: Identifying Test Box V.A.G 1598/22 Connected To Control Module Wiring Harness

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• Connect test box V.A.G 1598/22 (through my 1999) or test box V.A.G 1598/31 (from my 2000) to control module wiring harness.

Fig 4: 10-Pin Electrical Harness Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Check wiring between test box and connector for open circuit according to wiring diagram.

• Wire resistance: max. 1.5 Ω

• Check wires for short to one another, to vehicle Ground (GND) and to battery positive (B+).

• Specification: ∞ Ω

If wiring and resistance measurement values are OK:

• Replace engine control module → Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) J248 , replacing  .