NHTSA upgrades Stellantis probe involving Bosch fuel pump failures

WASHINGTON — The nation's top auto safety regulator has upgraded its investigation of high-pressure fuel pump failures in certain heavy-duty Ram diesel trucks.

According to a document made public Tuesday, NHTSA's Office of Defects Investigation is expanding its safety probe to include the Tier 1 supplier Robert Bosch, which makes the high-pressure fuel pumps. The expanded probe also includes any automakers who installed the part and are experiencing similar failures.

In October 2021, NHTSA launched its investigation of high-pressure fuel pump failures in 2019-20 Ram 2500, 3500, 4500 and 5500 heavy-duty trucks equipped with 6.7-liter Cummins turbodiesel engines after reports alleging incidents of stalling or loss of power. The upgraded probe also covers 2014-22 Ram 1500 trucks.

In addition to those vehicles, the probe covers Bosch's C4 fuel pumps, and 2021-22 Jeep Gladiator, 2014-20 Jeep Grand Cherokee and 2020-22 Jeep Wrangler vehicles. It also covers older models from BMW, including 2014-18 BMW 328D, 2014-16 BMW 535D and 2015-17 BMW X3 vehicles.

About 490,000 vehicles could be affected.

The upgraded probe — now an engineering analysis — is a required step before NHTSA can seek a recall.

NHTSA said an information request letter from BMW "indicated that failed pumps on their vehicles were caused by an interaction between pump internal components and U.S. market diesel fuel, leading to increased slip and eventual particle-generating wear surface."

The agency now will investigate whether a similar root cause is associated with vehicles previously recalled by Stellantis and if similar wear dynamics occur on pumps supplied to other automakers.

Stellantis spokesperson Eric Mayne said the automaker is continuing to lend its full cooperation to the agency.

Bosch said it was aware of the investigation and "will respond accordingly."

BMW spokesperson Jay Hanson said the automaker has been cooperating with NHTSA during the investigation and “will continue to do so.”

Separately, NHTSA also opened an investigation into more than 238,000 2022-23 Honda Civic vehicles after reports describing "sticky steering."

The agency's Office of Defects Investigation said it had received 145 complaints alleging "a momentary increase in steering effort" in those vehicles, mostly at highway speeds and after driving for a certain amount of time.

NHTSA has opened the safety probe — a preliminary evaluation — to assess the scope and severity of the potential problem and whether it poses any safety-related issues.

Most NHTSA investigations start as preliminary evaluations, in which agency engineers request information from the manufacturer, including data on complaints, injuries and warranty claims. The manufacturer also can present its view regarding the alleged defect and may issue a recall.

After the evaluation, NHTSA will either close the investigation or move into the next phase. If a safety-related defect exists, according to NHTSA, the agency may send a "recall request" letter to the manufacturer.