2004 Audi A4 Engine Stalling Fuel Pump Investigation Closed

NHTSA has concluded its preliminary evaluation, PE08027, into reports of engine stalling linked to fuel pump failures in the 2004 Audi A4. This investigation aimed to determine the scope and cause of these incidents.

NHTSA Investigation PE08027 Findings

During the 2004 Audi A4 investigation, Volkswagen AG (VW) suggested that excessive accumulation of foreign materials in the fuel filter could be a contributing factor. A clogged fuel filter might increase pressure on the fuel pump, potentially leading to issues.

VW indicated that engine stalls resulting from this condition are rare. These stalls would typically be preceded by symptoms such as "reduced engine power," "noise," or "hesitation." NHTSA's analysis of complaint and warranty data showed that the rate of engine stall incidents due to fuel pump failure was low, approximately 0.2 percent after three years in service.

Prior Fuel Pump Recalls (06V-017 and 07V-375)

It's important to distinguish this 2004 Audi A4 investigation from previous recalls. On January 17, 2006, VW issued a defect information report for a safety recall, 06V-017 (VW recall numbers M7 for Passat and JL for Audi A4 and A6). This recall affected approximately 74,000 model year 2003 Volkswagen Passat, Audi A4, and Audi A6 vehicles built from September 2002 through March 2003.

The cause for recall 06V-017 was identified as an unknown change in the material composition of the carbon-brush set within the fuel pump's electric motor. This could lead to increased wear, an inoperative fuel pump, and ultimately, a stoppage of fuel supply to the engine. On July 23, 2007, VW expanded the scope of this recall, assigned NHTSA recall number 07V-375, to include an additional 34,358 vehicles manufactured from August 2002 through April 2003.

Crucially, the 2004 Audi A4 vehicles that were the subject of PE08027 are not affected by the sub-supplier issue that prompted recalls 06V-017 and 07V-375. Production of the 2004 model year vehicles began several months after the amended production range identified in 07V-375.

Why the Investigation Was Closed

NHTSA determined that the fuel pump failures observed in the 2004 Audi A4 vehicles had different causes than the defect identified in the prior recall populations. Furthermore, these failures occurred at much lower frequencies. Consequently, NHTSA concluded that further investigation into this matter would not be an efficient allocation of agency resources.

Important Note for Owners

The closing of investigation PE08027 does not constitute a finding by NHTSA that a safety-related defect does not exist. The agency will continue to monitor complaints and other information relating to the alleged defect in the subject vehicles and will take further action in the future if warranted.

Owners experiencing symptoms such as "reduced engine power," "noise," or "hesitation" in their 2004 Audi A4 should consult a qualified technician for diagnosis.

Source

NHTSA Investigation PE08027