Fuel Pump Control Module, Testing

Special tools and workshop equipment required

Multimeter.
Electrical connector test lead set.

Test conditions

Battery voltage above 12.4 V.
Fuse -27- in Fuse Panel C is OK.
Fuel filter OK.
Ignition switched OFF.

Test procedure

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK

Start diagnosis

NOTE:

The battery must be fully charged in order to insure correct voltage readings during testing. Connect a battery charger to the battery if the system voltage is low.

-- Remove rear seat bench. Refer to the Repair Information.

-- Remove the Fuel Pump Control Module J538 from the retaining clips on the floor sealing cover -2-.

Fig 1: Identifying Fuel Pump Control Module, Retaining Clips & Floor Sealing Cover

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Disconnect the electrical harness connector -arrow- from the Fuel Pump Control Module J538.

Fig 2: Identifying Fuel Pump (FP) Control Module J538 Connector

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Turn the Ignition key ON.

-- Connect the multimeter ground lead to terminal -6- of the Fuel Pump Control Module J538 harness connector.

-- Connect the multimeter positive lead to terminal -1- of the Fuel Pump Control Module J538 harness connector.

Fig 3: Identifying Fuel Pump (FP) Control Module J538 Electrical Harness Connector Terminals 1 And 6

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- The meter should read within 1 volt of Battery voltage.

-- Turn the Ignition key OFF.

-- If voltage is below specification, locate wiring fault in ground or voltage supply circuit. Refer to wiring diagram for location.

-- If voltage is OK, connect multimeter positive lead to terminal -3- of the Fuel Pump Control Module J538 harness connector. The ground lead remains on terminal -6-

-- Crank the engine and note voltage displayed on multimeter during crank.

Specified value: Voltage should be within 2.5 volts of Battery voltage.

-- If voltage is below specification, locate wiring fault in the voltage supply circuit. Refer to wiring diagram for location.

-- If voltage is OK, connect multimeter positive lead to terminal -2- of the Fuel Pump Control Module J538 harness connector. The ground lead remains on terminal -6-

-- Crank the engine and note voltage displayed on multimeter during crank. Voltage should be 3.2 volts (+/-.4)

-- Turn the Ignition key OFF.

-- If voltage is below specification, check circuit from Fuel Pump Control Module J538 to ECM for open, short or high resistance and repair as necessary. If no circuit fault is found, replace Engine Control Module (ECM) - J623-. Refer to the Repair Information for replacement instructions.

-- If voltage is OK, reconnect the wiring harness to the Fuel Pump Control Module J538.

Test procedure for Fuel Pump

-- Remove the floor sealing cover to access the Fuel Delivery Unit (fuel pump).

-- Disconnect the harness connector from the Fuel Delivery Unit -arrow-.

Fig 4: Identifying Fuel Delivery Unit Connector

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Connect the multimeter positive lead to terminal -1- of the Fuel Delivery Unit harness connector.

-- Connect the multimeter ground lead to terminal -5- of the Fuel Delivery Unit harness connector.

-- Crank the engine and note voltage displayed on multimeter during crank. Voltage should be within 2.5 volts of battery voltage.

-- Turn the Ignition key OFF.

-- If voltage is below specification, replace the Fuel Pump Control Module J538.

-- If voltage is within specification, replace the Fuel Delivery Unit (Fuel Pump). Refer to the Repair Information.

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 .