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NHTSA Office of Defects Investigation

Preliminary Evaluation PE20-006: Intermittent Loss of Power Steering Assist

  • Closed

NHTSA's Office of Defects Investigation opened Preliminary Evaluation PE20-006 on May 1, 2020 and closed it on March 27, 2024. NHTSA's investigations file lists 12 models from 2 makes for it.

Updated daily from NHTSA's investigations file

Key facts

NHTSA number
PE20-006 (also written PE20006)
Investigation type
Preliminary Evaluation The first stage of most defect investigations: NHTSA's Office of Defects Investigation gathers basic information about a possible safety defect, including from the manufacturer.
Status
Closed March 27, 2024
Opened
Closed
Vehicle or equipment manufacturers
PACCAR Incorporated; Daimler Trucks North America, LLC; TRW Automotive, Inc.; ZF North America, Inc.
Components
Steering — Gear Box (OTHER THAN RACK AND PINION); Steering — Hydraulic Power Assist System
Vehicles and equipment
12 models from 2 makes, including the Peterbilt 330 and Peterbilt 337

A recall appears here only when NHTSA's investigations file links one to the investigation; NHTSA's summary or record can name others.

NHTSA's summary

As NHTSA's Office of Defects Investigation wrote it for Preliminary Evaluation PE20-006.

try.vin does not copy NHTSA's investigation documents; NHTSA's investigation record lists the ones NHTSA has published.

On May 1, 2020, the Office of Defects Investigation (ODI) opened PE20006 to investigate complaints of intermittent loss of power steering assist in Daimler Truck North America (DTNA), Volvo Trucks of North America (Volvo) and PACCAR vehicles equipped with a ZF/TRW (TRW) THP60 steering gear. The investigation focused on 2010-2020 DTNA Freightliner Cascadia, M2 and WST; Volvo VN, VAH and VHD and PACCAR 337, 365, 389, 567, 579 model vehicles.

Field reports and interviews with fleet drivers allege that high power steering fluid temperatures could result in internal seal and bearing failures causing pressure fluctuation, affecting left and right-hand turns. The inability of the driver to steer the vehicle as intended can increase the risk of a crash and injury. ODI analyzed data provided by TRW, DTNA, Volvo, and PACCAR in response to individual information request letters.

ODI found that most failures occurred within the first two years and/or 50,000 miles of service. The claim rate decreased with time and miles in service and remained less than 0.5%. ODI normalized data from each of the manufacturers and determined that there was not a substantial difference in the failures.

Additionally, TRW improved a seal in the steering gear in December 2015.

Trucks built on or after 2016 (as 2017 and newer model years) show a decreasing trend of failures. In view of the overall low failure rate, the nature of early-life failure, and failure rate trending downward for model years 2017 and newer, this Preliminary Evaluation (PE) is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist.

The Agency reserves the right to take additional action if warranted by future circumstances. To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

Vehicles and equipment listed for this investigation

NHTSA's investigations file lists these vehicles and equipment for Preliminary Evaluation PE20-006. A listed model year means only that an investigation names it; it says nothing about any particular vehicle. Model years with a try.vin recall page link to that page's NHTSA investigations section.

Freightliner

All Freightliner recalls

Peterbilt

All Peterbilt recalls

TRW

  • TRW (model not given)

    • model year not given

ZF

  • ZF (model not given)

    • model year not given

What an NHTSA investigation is

NHTSA's Office of Defects Investigation (ODI) looks into possible safety defects in vehicles and equipment, often after owner complaints. An investigation usually starts as a Preliminary Evaluation, or as a Recall Query when it concerns whether an existing recall covers the right vehicles or fixes the problem, and ODI can upgrade it to a more detailed Engineering Analysis. A Defect Petition asks NHTSA to open an investigation, and Audit and Equipment Queries are administrative investigations into whether companies complied with federal vehicle safety requirements, such as reporting, recall and certification rules.

An open investigation is not a finding that a safety defect exists, and NHTSA can close one without a recall.

To see whether a specific vehicle has an open recall, enter its VIN at nhtsa.gov/recalls.

Free VIN check: decode a VIN to see its year, make and model.

Sources

NHTSA's investigation record for PE20-006

Investigation details come from NHTSA's investigations file, which try.vin imports once a day. The investigation types are described from the U.S. Department of Transportation Inspector General's May 2023 report on NHTSA's Office of Defects Investigation, NHTSA's petition rules (49 CFR Parts 552 and 557) and NHTSA's Office of Defects Investigation procedures. How try.vin reads NHTSA investigations.