Fuel Pumps, Checking Function And Power Supply

WARNING: This page is about a different car, the 2023 Volkswagen Atlas. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Trim Removal Wedge:3409
Multimeter, for example Digital Multimeter:FLUKE83III
Connector Test Set:VAG1594D
Vehicle Diagnostic Tester

Test Conditions:

The battery voltage must be at least 11.5 V. Charge the battery if necessary. Refer to BATTERY, CHARGING .
Fuel Pump Control Module -J538- fuse OK. Refer to the appropriate Wiring Diagram.
Fuel Pump Control Module -J538- is OK use the Vehicle Diagnostic Tester.

Test Sequence:

NOTE:

The output diagnostic test mode checks the fuel pump function.

-- Connect the Vehicle Diagnostic Tester.

-- Switch the ignition on.

-- Select the fuel pump output diagnostic test mode in OBD.

The fuel pump must now accelerate slowly up to the maximum RPM.

NOTE:

The fuel pump runs very quietly.

If the output diagnostic test mode is performed several times in succession, the engine may need to be started briefly before repeating the output diagnostic test mode.

-- Switch off the ignition.

If the Fuel Pump Does Not Start:

-- Remove the installation opening cover. Refer to FUEL DELIVERY UNIT COVER, REMOVING AND INSTALLING .

-- Remove the Fuel Pump Control Module -J538- with the connected wiring harness. Refer to Fuel Pump Control Module -J538-, REMOVING AND INSTALLING .

-- Remove the Fuel Pump Control Module -J538- toward the inside between the fuel tank and the floor panel.

-- Move the Fuel Pump Control Module -J538- together with the wiring harness to the side.

-- Pull on the connector on the Fuel Pump Control Module -J538- without pushing the locking mechanism to make sure it is secure. Repeat the fuel pump function test if the connector was not connected correctly.

-- Release and remove the connector from the Fuel Pump Control Module -J538-.

-- Check the contacts on the connector and on the Fuel Pump Control Module -J538- for damage.

-- Check the voltage supply between contacts -3 and 4- using the :FLUKE83III . Refer to the appropriate Wiring Diagram.

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- To do so, use the :VAG1594D .

-- Switch the ignition on.

Specified value: approximately battery voltage

If the Specified Value Is Not Obtained:

-- Locate and repair the open circuit according to the wiring diagram. Refer to the appropriate Wiring Diagram.

-- Pull on the connector -arrow- without pressing the release to make sure the connection is secure. Repeat the fuel pump function test if the connector was not connected correctly.

Fig 1: Fuel Pump Control Module Connector

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Release and disconnect the connector.

-- Check the contacts on the connector and on the fuel delivery unit for damage.

-- Check the wiring harness between the Fuel Pump Control Module -J538- and the fuel delivery unit. Refer to the appropriate Wiring Diagram.

If No Faults Can Be Found:

-- Remove the fuel delivery unit. Refer to FUEL DELIVERY UNIT/FUEL LEVEL SENSOR, REMOVING AND INSTALLING .

-- Check the wires between the flange and the fuel pump with an ohmmeter for flow.

Fig 2: Checking Electrical Circuit Between Terminals And Of Fuel Delivery Unit For Resistance

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

-- Inspect the contacts for damage.

If No Open Circuits Are Found:

-- If the fuel pump is faulty, replace the fuel delivery unit. Refer to FUEL DELIVERY UNIT/FUEL LEVEL SENSOR, REMOVING AND INSTALLING .