Headlight failure or clouding on the 2004 Toyota Prius
When headlight failure or clouding gets reported
Owners of the 2004 Toyota Prius report headlight failure or clouding at a median of 105,000 miles. A quarter of the reports come in before 80,000 miles and a quarter after 140,000 miles, from 119 reports that carried an odometer reading.
A part like this is normally expected to survive 88,000 miles. It is the 1st most-reported problem on this model year.
The mileage distribution
The reported range runs from 50,000 miles at the tenth percentile to 170,000 miles at the ninetieth, a spread of 120,000 miles across the middle 80% of reports.
A spread this wide points at use rather than design. Towing, climate, service history and city mileage all move a failure like this, so the median is a weak guide to any individual car.
5% of the dated reports were filed under 36,000 miles.
The whole distribution
| 10th | 25th | Median | 75th | 90th |
|---|---|---|---|---|
| 50,000 miles | 80,000 miles | 105,000 miles | 140,000 miles | 170,000 miles |
Read the 10th percentile as “one report in ten arrived this early”. Exact figures are shown in this table because it is the table of record; everywhere else on the site they are rounded to the precision the sample can carry.
What a percentile can and cannot tell you here
These five numbers describe the readings owners gave, in order. The median is the middle one: half the reports arrived below it. The 10th and 90th are the edges of the bulk of the distribution, and the distance between them is the part worth reading. A tight spread — say 70,000 to 95,000 miles — points at something that wears out on a schedule, and the schedule is knowable. A wide one, 20,000 to 190,000, points at a fault that hits some cars and never troubles others, which means the mileage on the listing in front of you tells you very little about your odds.
What these figures are not is a survival curve. Every reading here comes from a car whose owner filed a complaint, so the sample contains only failures: it cannot say what share of the fleet made it past 150,000 miles untouched, because those owners had nothing to report. Nor is the mileage the moment of failure — it is the odometer reading as recalled at the time of filing, which may be weeks later and is sometimes rounded to the nearest ten thousand by the person typing it.
Percentiles are shown at all only once 8 readings exist for the vehicle and mode. Below that the middle of a handful of numbers is noise wearing a decimal point, so the figures are withheld rather than dressed up.
What happens, and what it costs
Putting it right typically runs $150–$1,800 at an independent US shop. That range is an editorial estimate held in this site's failure-mode catalogue, not a figure from NHTSA, and it is a repair cost rather than a diagnosis cost.
The same failure on other years
The same failure is reported on 12 model years of this car. It shows up earliest on the 2006, at a median of 47,000 miles, and latest on the 2004 at 105,000 miles.
By volume the 2007 carries the most reports, with 718; the 2004 has 136. A mode that appears across most years of a model is usually a design choice rather than a bad batch.
If one year stands out to the left, that is the year to avoid; if the whole line sits at a similar mileage, this is wear rather than a defect in one production run.
Tick median reported mileage Solid middle half of reports Faint 10th to 90th percentile Colour how bad the failure is when it happens
What owners wrote
Verbatim from NHTSA complaint narratives, trimmed for length. The mileage is the one the owner gave.
Tl*the contact owns a 2004 toyota prius. While driving in any type of weather, one headlight would dim followed by the other. However, both headlights could dim simultaneously. The failure occurs intermittently. The vehicle's speed was not a factor. During the failure, all of the other lights were operational. The contact has had the lights repaired due to safety concerns. The current mileage is 90,000 and failure mileage was 70,000.
2004 prius, 84,00 miles. Intermittent headlight failure, both right and left. Headlight(s) would go out while driving at night. Dealer said it was HID computer and the repair bill is $1140!!!! Researching on internet reveals this is a common problem. It is definitely safety relayed and I feel toyota should make the repair at no charge. I'm not excited about replacing the computer not only because of the cost, but can I expect the problem to repeat in a few years? *tr
Driver side HID headlight goes out, but reignites (most of the time) after headlight switch is turned off and then back on. Recently, the drivers side light was out (and would not reignites), and the passenger side light went out as well, leaving me without headlights. The passenger side light did reignites after turning the switch off and back on. *tr
Also reported on the 2004 Toyota Prius
Other electrical problem
Other lighting problem
Other engine problem
Other speed control problem
Other brake problem
Other powertrain problem
How far this goes
Complaints are voluntary, so 136 is a floor and not a count of affected cars. Mileages are typed in by owners and cluster on round numbers. And the mode itself is assigned by software reading the complaint text, which is reliable in bulk and fallible one report at a time.
Questions this page answers
At what mileage does headlight failure or clouding happen on the 2004 Toyota Prius?
Across 119 owner reports that included an odometer reading, half were filed by 105,000 miles. A quarter were filed before 80,000 miles and a quarter after 140,000 miles. These are the mileages owners reported when they complained, not a prediction for any individual car.
How common is headlight failure or clouding on the 2004 Toyota Prius?
136 reports have been filed with NHTSA, about 1.2 per 1,000 vehicles. Complaints are voluntary, so this is a floor rather than a count of affected cars.
What this is and is not. These are the mileages at which owners chose to complain to a federal agency, which is not the same as the mileage at which the part fails on every car. It skews toward failures that happened outside warranty, cost real money, or frightened someone. It is still the only public dataset that carries failure mileage at all, and the shape of a few hundred readings is informative even when a single one is not. Methodology · JSON · this failure on other cars
Source Owner complaints and recall records published by the US National Highway Traffic Safety Administration, model years 1996–2027 Figures rebuilt Published by AtWhatMileage How every figure is computed