NHTSA Investigation Stages: From Complaint to Recall
What the letters PE, EA, RQ, DP and AQ mean on a federal safety probe, how long each stage is meant to take, and when an owner should act.
An NHTSA defect investigation usually starts as a preliminary evaluation (PE), can be upgraded to an engineering analysis (EA), and ends with either a closure or a recall. Separate tracks cover recall queries (RQ) on recalls that may not work, defect petitions (DP) filed by the public, and audit queries (AQ) on reporting. An open investigation is not a recall, and it does not by itself entitle owners to a free repair.
The work is done by NHTSA’s Office of Defects Investigation (ODI). Every case gets a code that starts with the stage letters, followed by the two-digit year and a sequence number, so an engineering analysis opened in 2026 starts with EA26.
What starts an NHTSA investigation?
Most investigations start with patterns in data the agency already collects. ODI screens owner complaints, manufacturer reports of deaths, injuries and warranty claims, technical service bulletins, and crash and fire reports. There is no fixed number of complaints that triggers a case. NHTSA says a single complaint can be enough when the risk is serious.
Many problems never become formal investigations because the manufacturer recalls the vehicles after ODI raises questions. That is one reason owner complaints matter even when nothing seems to happen. Our guide on how to report a vehicle safety problem walks through the form.
What are the stages, and how long does each take?
NHTSA sets target durations for each type of investigation, though complex cases often run longer. These are the targets NHTSA publishes on its investigations resource page, as of November 2026.
| Stage | Code | What happens | NHTSA target |
|---|---|---|---|
| Defect petition | DP | Anyone asks NHTSA to open an investigation; ODI grants or denies it | About 4 months |
| Preliminary evaluation | PE | ODI requests complaints, injury, warranty and parts data from the manufacturer | About 8 months |
| Recall query | RQ | ODI checks whether an existing recall covers enough vehicles or whether the fix works | About 8 months |
| Engineering analysis | EA | Deeper study, sometimes with testing, surveys and inspections | About 18 months |
| Audit query | AQ | Review of whether a manufacturer met its reporting or recall duties | Varies |
What is a preliminary evaluation?
A preliminary evaluation is the first formal step, in which ODI sends the manufacturer an information request and studies the answers. The request typically asks for every complaint, lawsuit, field report, warranty claim and parts sale related to the suspected problem, plus the company’s own analysis.
A PE ends in one of three ways. The manufacturer can decide to recall the vehicles, ODI can close the case because the data do not show a safety defect, or ODI can upgrade it to an engineering analysis. ODI posts an opening resume and a closing resume for each case, so you can read the reasoning.
What is an engineering analysis?
An engineering analysis is a deeper probe that can include vehicle testing, crash data review and inspections of failed parts. It often covers a larger population than the PE that preceded it.
At the end of an EA, ODI either closes the case or recommends that the agency seek a recall. Most manufacturers recall voluntarily at this stage. If a company refuses, NHTSA can issue an initial decision that a defect exists, hold a public meeting and then order a recall, which the company can contest in court. That path is rare.
What do recall queries and defect petitions mean for owners?
A recall query means NHTSA is questioning a recall that already exists. ODI opens one when owners keep reporting failures after the repair, or when similar failures show up in vehicles outside the recall population. In 2024 NHTSA opened a recall query to assess whether Tesla’s Autopilot recall 23V838 had worked. An RQ can lead to a larger recall or a new remedy.
A defect petition is a formal request from the public under federal rules in 49 CFR Part 552. If ODI grants it, an investigation opens. If ODI denies it, the reasons are published in the Federal Register. Petitions have led to real cases, including a 2018 petition on non-crash engine fires that became two preliminary evaluations.
When should owners act during an investigation?
Owners should act right away if the car shows the symptom under investigation, and file a complaint even if the car seems fine after a repair. During an investigation there is usually no free repair yet, so the steps are practical:
- Look up your VIN at nhtsa.gov/recalls and read the investigations listed for your model.
- Read the opening resume to see which symptom ODI is studying.
- If your car has that symptom, file a complaint with NHTSA and tell your dealer in writing.
- Keep repair invoices. If a recall follows, many automakers reimburse owners who paid for the same repair earlier.
- Check your VIN again every month or two until the case closes.
If a recall does come, the repair is free at a franchised dealer, subject to the federal age limit on remedies. The details are in our guide to whether recall repairs are free.
Bottom line
A PE or EA on your model means NHTSA is studying a possible defect and no free repair exists yet. Keep your receipts, report any symptom to NHTSA, and run the VIN check until the case closes or turns into a recall.
FAQ
Does an NHTSA investigation mean my car will be recalled?
No. Many investigations close without a recall because the data do not show a safety defect. Others end with a voluntary recall before the probe reaches the engineering analysis stage.
Where can I read the documents for an investigation?
NHTSA posts the opening resume, information requests, manufacturer responses and closing resume for each case. You can find them by searching your vehicle at nhtsa.gov/recalls and opening the investigations tab.
Can I be paid back for a repair I paid for before a recall?
Often yes. Manufacturers must have a plan to reimburse owners who paid for the remedy before the recall within a set window, and the recall notice explains how to claim it. Keep invoices that show the part and the problem.
Can I ask NHTSA to open an investigation?
Yes. Anyone can file a defect petition in writing, explaining the problem and the facts behind it. A complaint filed online also feeds the same screening process and is the easier first step.
