P0442 OBD-II Trouble Code: Evaporative Emission Control System Leak Detected (Small Leak)

Our certified mechanics come to you · Get a fair and transparent estimate upfront

Red-stars EXCELLENT RATING ON

Cost of diagnosing the P0442 code

P0442 is a diagnostic trouble code (DTC) for "Evaporative Emission Control System Leak Detected (Small Leak)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $114.99 . Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.0 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.

Cars Estimate Credit towards follow-up repair Earliest Availability
Ford $114.99 $20.0
Toyota $114.99 $20.0
BMW $124.99 $20.0
SCHEDULE P0442 DIAGNOSTIC Get a fair and transparent estimate upfront

P0442 code definition

P0442 is a diagnostic trouble code (DTC) that is seen when a evaporative emission control system malfunction is present. This code may be seen with other EVAP system codes.

What the P0442 code means

P0442 is present in vehicles that have a small leak in the EVAP system. The ECU carefully monitors the EVAP system for any leaks or irregularities, when a small leak is detected the ECU set a Check Engine Light to be displayed on the dashboard.

What causes the P0442 code?

  • Faulty or loose fuel cap
  • EVAP system line leak
  • Charcoal canister leak
  • Fuel tank leak
  • Failed vent or purge valve

What are the symptoms of the P0442 code?

  • The Check Engine Light being present on the dashboard.

  • Some vehicles may exhibit a slight drop in gas mileage with the EVAP leak

How does a mechanic diagnose the P0442 code?

  • Hooks up a scan tool to the vehicle's DLC port and checks for any codes present

  • Examines the freeze frame data associated with the code which shows the circumstances that were present with the vehicle at the time of the malfunction

  • Clears the codes and test drives the vehicle

  • Performs a visual inspection of the EVAP system, looking for any obviously cracked or broken components, and loose or damaged EVAP lines

  • Checks for cracks in the fuel tank or charcoal canister

  • Inspects the gas cap for proper fitment and condition, then tests with a gas cap tester

  • Uses a scan tool to monitor tank pressure and confirm if a leak is present

  • Tests the EVAP system solenoids and valves with scan tool

  • Performs a smoke test on the EVAP system, looking for smoke that indicates a vapor leak

Common mistakes when diagnosing the P0442 code

Qualified technicians should have little problem diagnosing P0442 as long as all steps are followed in the proper order and none are skipped.

Commonly, the gas cap is the cause of P0442, if the gas cap is overlooked it can waste time and energy diagnosing other components.

How serious is the P0442 code?

The P0442 generally has no adverse symptoms other than the Check Engine Light being present. When this code is seen, it means that the EVAP system is leaking fuel vapors into the atmosphere. A slight dip in fuel economy may be noticed with this code.

What repairs can fix the P0442 code?

  • Replacing the gas cap
  • Replacing the fuel tank
  • Replacing the charcoal canister
  • Replacing the EVAP system lines
  • Replacing the purge or vent valves

Additional comments for consideration regarding the P0442 code

Professional level tools make diagnosing the P0442 leak much easier and accurate. An advanced scan tool that allows access to live data and control of the EVAP system is very helpful when dealing with the P0442 code or any EVAP code in general.

Some vehicles have the ability to be commanded with the scan tool to test the EVAP system for proper operation of all components, and can be used to help isolate which part of the system the fault or leak lies.

Since they are fuel vapors, most of the EVAP leaks are much smaller than the eye can see. A smoke test is performed to find hard-to-detect fuel vapor leaks. This is done by using a specialized smoke machine that pressurizes the fuel system and adds smoke so that small leaks will be visible.

Need help with a P0442 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

Check Engine Light
P0442
trouble codes

No more waiting rooms! Our mechanics will come to you to diagnose and fix the P0442 code.

SCHEDULE P0442 DIAGNOSTIC
Get a $20 credit for the follow-up repair

Recent Check Engine Light is on Inspection reviews

Excellent Rating

(7400)

Rating Summary
6879
249
58
41
173
6879
249
58
41
173
 at YourMechanic

David

13 years of experience
393 reviews
David
13 years of experience
Chevrolet Malibu L4-2.4L - Check Engine Light is on Inspection - Marietta, Georgia
He explained everything to me in detail on what I needed to know about my car. Definitely recommend him for getting the job done.
 at YourMechanic

Raymond

37 years of experience
402 reviews
Raymond
37 years of experience
Toyota Camry L4-2.2L - Check Engine Light is on - Las Vegas, Nevada
Raymond did a great job however I was charged for two hours labor and he was only here less than 45 minutes. should I expect this on future appointments with your mechanic ?
 at YourMechanic

Shane

17 years of experience
217 reviews
Shane
17 years of experience
Volkswagen EuroVan V6-2.8L - Check Engine Light is on Inspection - Austin, Texas
Arrived on time. Explained the issues he found and how he will fix it. I have parts on order and will schedule an appointment to have Shane install the parts when they arrive.
 at YourMechanic

Kanstantsin

19 years of experience
51 reviews
Kanstantsin
19 years of experience
Ford F-150 V8-4.6L - Check Engine Light is on Inspection - Littleton, Colorado
Kanstantsin arrived early. Was very courteous and professional. Will highly recommend to anyone. Thank you Kanstantsin.


Related questions

Check engine light on
The code P0442 (https://www.yourmechanic.com/article/p0442-obd-ii-trouble-code-evaporative-emission-control-system-leak-detected-small-leak-by-spencer-clayton) is for a very small leak in the evaporative system of the fuel tank and its vent system. A leak in the gas cap is the most common cause of this code and the gas cap...
Small Evap emissions leak on a Subaru Impreza
The gas caps are really common for the P0442 code (https://www.yourmechanic.com/article/p0442-obd-ii-trouble-code-evaporative-emission-control-system-leak-detected-small-leak-by-spencer-clayton). A gas cap costs like eight bucks. Get another gas cap and put it on and pray that it's that. Because if it's not that, it is generally time...

More related articles

P0815 OBD-II Trouble Code: Upshift Switch Circuit
What What the P0815 code means Your vehicle’s powertrain control module (PCM) has recognized a problem in the electrical circuit of the upshift switch circuit. The upshift/downshift switch is located in the passenger compartment near your vehicle’s shifter. Please note...
P0372 OBD-II Trouble Code: Timing Reference High Resolution Signal A Too Few Pulses
P0372 code means less pulses than normal have been detected on the sensor disk on the injection pump due to faulty crankshaft or crankshaft sensor.
P0843 OBD-II Trouble Code: Transmission Fluid Pressure Sensor A Circuit High
P0843 means that the fluid pressure is not what is being read by the sensor due to a faulty sensor, solenoid or due to dirty fluid or blocked lines.

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com