AIPlateChecker← Check a car

MOT failure item explained

“Exhaust lambda reading after 2nd fast idle outside specified limits”

Recorded on 517 of the 25,257 cars checked on this site. It is a failure item.

Seen this on a car? Check it free

Every MOT test, every advisory, the mileage record and a condition score, in seconds. No sign-up.

Buying it? The full history report adds finance, write-off, stolen and keeper checks.

Cars with it
517
of 25,257 checked
Share of cars
2.0%
at least once
Recorded as
Fail
99.2% of 601 visits
Back next time
8.8%
of 480 follow-up visits

What it means

Petrol cars have their exhaust gas measured at a fast idle. Lambda is the balance of air to fuel in that gas. This entry means the reading was still outside the limits set for the car after the second attempt.

It is a failure, and the car cannot pass until the emissions are back within limits. A pass recorded afterwards shows the retest was done.

How it shows up in the records

Fail 99.2%Fail, put right during the test 0.8%
8.8% came back
The same entry, on the same part of the car, was recorded again at the next test in 8.8% of cases.
45,239 miles
Median recorded mileage when it first appeared, on cars a median of 7 years old. From the 94 cars whose whole MOT history is recent enough to compare.

Share of cars with this entry, by year of manufacture

0.0%1971–730.0%1980–820.0%1983–850.0%1986–880.9%1989–912.5%1992–944.1%1995–976.1%1998–006.9%2001–034.5%2004–064.3%2007–093.4%2010–122.2%2013–151.2%2016–180.4%2019–210.0%2022–24

Models where it is recorded most

ModelCars with itShareSame-age cars
Vauxhall Astra17 of 2048.3%2.6%
Volkswagen Polo19 of 2607.3%2.3%
Fiat 50011 of 1766.3%1.9%
Ford Fiesta32 of 4876.6%2.3%
TVR Tuscan5 of 5010%5.9%
Honda Jazz21 of 4984.2%2.5%
Honda Civic10 of 2783.6%2.2%
Suzuki Swift6 of 1973.0%1.8%

Models with 20 or more cars checked here. “Same-age cars” is the share among all checked cars built in the same years, so an older model is compared with older cars.

What to check before you buy

  • Find the failed test and the pass that followed it, and note how long it took.
  • Ask for the invoice showing what was done to get it through.
  • Turn the ignition on and check that the engine warning light comes on, then goes out once the engine is running.
  • Look through the later tests for the same failure coming back.

Cars checked here with this entry

Other exhaust and emissions entries explained

Exhaust has a minor leak of exhaust gases

Checking a car with this on its MOT?

Repair costs depend on the car, so this page does not quote one. Enter the plate and the free report estimates them for that car, alongside every test and advisory on its record.

Check a car’s MOT history

Counts are of cars checked on this site, from official public records. Updated 19 Sept 2026 · figures as of 4 Oct 2026. All MOT entries explained.