Question 1

Will a P0442 code cause my car to fail its MOT in Winchmore Hill?

Accepted Answer

Yes. If your Engine Management Light is illuminated when the MOT tester checks it, the vehicle will receive an immediate MOT failure. P0442 triggers the EML, so the car must be properly diagnosed and the fault resolved before the MOT test — or retested after repair.

Question 2

How much does P0442 EVAP diagnosis cost at MnF Motors?

Accepted Answer

Diagnostic time for a P0442 fault starts from around £55–£75 at MnF Motors. This covers a full scanner read, smoke test to locate the leak, and a written report of findings. Any repair cost is quoted separately and clearly before work begins — no surprises.

Question 3

Can I just replace the fuel cap to fix P0442?

Accepted Answer

Sometimes, yes — a worn or loose fuel cap is one of the most common causes of P0442. But it is not always the cap. A cracked EVAP hose, leaking charcoal canister or a faulty purge valve can produce exactly the same code. Replacing the cap blindly and hoping the light goes out wastes money if the real leak is elsewhere. A smoke test at MnF Motors confirms the source first.

Question 4

How long does EVAP leak diagnosis and repair take?

Accepted Answer

The smoke test itself typically takes 30–45 minutes. If the repair is straightforward — such as a new fuel cap or a short EVAP hose — the whole job is often completed the same day. More involved repairs like a charcoal canister replacement are usually done within 24–48 hours depending on parts availability.

Question 5

Is MnF Motors able to carry out the MOT test and P0442 repair in one visit?

Accepted Answer

Yes. MnF Motors is a fully authorised MOT test station. If your car comes in with a P0442 code and an active EML, we can diagnose the fault, carry out the repair, clear the code, confirm the light is off, and then run your MOT — all without the vehicle needing to leave the site. This saves Winchmore Hill customers significant time and hassle.