What the NHTSA investigation stages mean

Where an investigation comes from

Most recalls start with the manufacturer. NHTSA's recall booklet says most decisions to recall are made voluntarily, before the agency is involved. Investigations are for the rest: problems that owners, crash data or the manufacturer's own reports suggest might be a safety defect, where nobody has acted yet.

NHTSA's Office of Defects Investigation (ODI) describes its work in five stages. It collects data, including owner complaints, manufacturer bulletins, the early warning reports manufacturers must file, and crash reports. It reviews that data for anything that looks like a trend. It digs into promising issues, using sources that range from insurance records to auction listings and owner forums. It opens a formal, public investigation when the evidence is there. And it manages recalls once they happen.

Only the last two stages are visible from outside. That's what the codes on an investigation (PE, EA, DP, RQ) describe.

The four investigation types

Defect petition (DP). Anyone can petition NHTSA to open an investigation. ODI reviews the petition and either grants it, which opens an investigation, or denies it and publishes its reasons in the Federal Register. NHTSA aims to finish a petition review within four months.

Preliminary evaluation (PE). This is the usual opening move. NHTSA's description of its risk-based process calls the PE the first phase, prompted when complaints or manufacturer service bulletins suggest a safety defect. ODI asks the manufacturer for data on complaints, crashes, injuries, warranty claims and parts sales, and the PE ends in one of two ways: it's closed, or it's upgraded to an engineering analysis. NHTSA's target is eight months.

Engineering analysis (EA). The deeper phase. ODI may test vehicles or analyze parts, and the manufacturer gets to argue its side. An EA ends with either a recall or a closing. NHTSA's target is 18 months, and its booklet says investigations are generally resolved within that window.

Recall query (RQ). This one looks at a recall that has already happened. NHTSA's recall management staff watch whether a recall covered all the vehicles it should have, whether parts are reaching dealers, and whether the fix actually works. When something looks wrong, a recall query can lead to a wider recall or a changed remedy. The target is eight months.

How long they've really taken

Here are the investigations that touch the vehicles on this site, counted once each, with the time from opening to closing:

The last column counts investigations that NHTSA's file links to a recall number. It's a rough measure of outcome, since a recall can follow an investigation without being linked in the file. Even so, the gap is wide: 29% of preliminary evaluations carry a recall number, against 53% of engineering analyses. By the time something reaches an EA, NHTSA thinks there's a real chance of a defect.

NHTSA's targets work out to about 240 days for a preliminary evaluation and about 550 for an engineering analysis. The medians here are 141 and 387 days. A median hides the long tail, though. 45 of the closed engineering analyses here took more than two years, so an open investigation on your car may take a while.

How an investigation ends in a recall

Usually the manufacturer blinks first. NHTSA's process document says investigations are ordinarily resolved before any formal finding, when the manufacturer files its own recall report. NHTSA calls these influenced recalls.

If the evidence supports a defect and the manufacturer hasn't recalled, ODI presents the case to a panel of agency experts. If the panel agrees, NHTSA sends the manufacturer a recall request letter.

Can NHTSA force a recall?

Yes. The agency can make a formal decision that a safety defect exists and order a recall. The manufacturer can challenge that order in federal district court, and once the case is in court, NHTSA carries the burden of proof. The Department of Justice can also go to court to compel a recall.

While a challenge is pending, the manufacturer doesn't have to fix cars, though it may be required to tell owners about NHTSA's decision. NHTSA's booklet advises that if you pay for the repair yourself during that time and the court upholds the decision, you may be entitled to reimbursement, so keep the receipts.

What an open investigation means for you

An open investigation isn't a recall. There's no free repair yet and nothing the dealer is obliged to do. It does mean NHTSA has seen enough to look closely, so a few steps are worth taking:

• Read the opening summary. Each investigation on this site's vehicle pages links to NHTSA's text, which says what failure is alleged and how many complaints ODI had counted.
• File a complaint if it's happened to you. Complaints are evidence, and our guide on filing with NHTSA covers what to include.
• Keep repair records. If an engineering analysis ends in a recall, the reimbursement window for repairs you paid for can start as early as the date the EA opened. Our reimbursement guide explains the rule.
• Check again. Investigations and recalls show up on NHTSA's recall search once they're public.

Reading the code

The investigation number tells you the type and the year it opened. EA19-005 is an engineering analysis opened in 2019, and PE24-001 is a preliminary evaluation opened in 2024. When an investigation is upgraded, the new one gets its own number, and its summary sometimes names the one it grew out of. EA19-005's summary, for one, says it was upgraded from RQ18-002.

Across the vehicles on this site, NHTSA's files hold 1,188 investigations, 65 of them still open.