Contour Enthusiasts Group Archives Forums General Troubleshooting Failed emission test 98 Mystique

My Mystique with 89000 KM failed the emission test today (Ontario Canada). Cost me a total of $610 CAD dollars to repair the problem. $90.00 for a emission diagnostics and the remainder to replace the 2 O2 sensors and a emmission retest.

Why would the O2 sensors fail?

They sometimes fail around 70k to 80k miles due to regular wear and tear. 89k km is a little early, but not completely outrageous.

Although O2 sensors are supposed to last 100k miles (160,000km), some die earlier.

Contaminated gas, excessive idling, rich A/F operation, flooding, oil consumption, some fuel additives, and especially ethylene glycol antifreeze contamination will contribute to the early failure of O2 sensors.

Just be glad you don't have a five year old electric car that needs an $8000 set of batteries.

Hey Billnah,

I'm a EMISSIONS INSPECTOR in Burlington, Ontario...can You forward the test results to product_from_poland@hotmail.com Just curious to see. Thanks,

Bartek

Presumably you had CEL light on before taking it in for test? Surprising that 2 of the 4 oxygen sensors needed to be replaced at the same time, unless you had been operating car with CEL on for some time.

Did it actually fail the sniffer test before the work was done?

The $400 US bill sounds about right for dealer, you might have saved on sensor cost getting it fixed elsewhere with non-Ford parts.