CEL P0446 After Replacing MAF

[KevinH90]

Last week, I had to replace the MAF on my 2000 2.7 Boxster with 34k on it. While driving to work today, the CEL lit. I had the code read at Autozone and it is P0446 - a malfunction exists in the electical circuit for the vent control in the evaporative emission control system.

Could there be a relationship between this problem and the MAF replacement? (The tech who replaced the MAF said that it had become "corrupted" and was causing the car to run too rich.)

Is it possible that this code could be generated by a damaged gas cap? The person who pulled the code suggested that could be the problem.

Based on my search of this forum, it appears that it could also be a problem with the purge valve.

Thanks for any assistance.

Edited October 13, 2006 by KevinH90

[insite]

Could there be a relationship between this problem and the MAF replacement? (The tech who replaced the MAF said that it had become "corrupted" and was causing the car to run too rich.)

Is it possible that this code could be generated by a damaged gas cap? The person who pulled the code suggested that could be the problem.

Based on my search of this forum, it appears that it could also be a problem with the purge valve.

it is a purge valve code. it's probably not related to the MAF replacement. i'm not sure with the Box, but on my G35 the car will throw a similar code if the gas cap is even loose, so it's possible the gas cap could be the problem.

[lufteknic]

Could there be a relationship between this problem and the MAF replacement? (The tech who replaced the MAF said that it had become "corrupted" and was causing the car to run too rich.)

Is it possible that this code could be generated by a damaged gas cap? The person who pulled the code suggested that could be the problem.

Based on my search of this forum, it appears that it could also be a problem with the purge valve.

it is a purge valve code. it's probably not related to the MAF replacement. i'm not sure with the Box, but on my G35 the car will throw a similar code if the gas cap is even loose, so it's possible the gas cap could be the problem.

before slapping parts on, lets see what is going on. p0446 is a EVAP fault, and is a fairly common failure on 986/996 cars. with PST equipment one can check components, as well as other diagnostic tests to confirm the issue. Gas caps have been known to cause problems, but most of the cars have had this issue fixed eons ago.

Also, and this is very important with any OBDII car: DO NOT try to pack the gas tank full of fuel, this can cause a host of problems. When the gas nozzle clicks off, stop pumping fuel.

[KevinH90]

before slapping parts on, lets see what is going on. p0446 is a EVAP fault, and is a fairly common failure on 986/996 cars. with PST equipment one can check components, as well as other diagnostic tests to confirm the issue. Gas caps have been known to cause problems, but most of the cars have had this issue fixed eons ago.

Also, and this is very important with any OBDII car: DO NOT try to pack the gas tank full of fuel, this can cause a host of problems. When the gas nozzle clicks off, stop pumping fuel.

Good suggestion. I'm planning to come see you next week - if I can ever get out of work before 6:00.

The previous owner gave me every receipt he had - including minor items like car washes. I didn't see a receipt for a gas cap, so I'm assuming I have the original.

This is certainly a more benign problem than the MAF failure. The car runs fine, but the glowing orange light is interfering with my enjoyment of the car.

[KevinH90]

I know that the only way I'm going to find the real solution to my problem is to leave the car with Lufteknic for a day or two, but I thought I would update this thread.

Saturday October 14 - Change oil and filter - Mobil 0W40 - Car drove fine

Monday October 16 - Brought car to Lufteknic (nice shop and good people) for diagnosis. They did some quick checks, but they will need more time to make a thorough analysis and narrow down the possible cause. They reset the check engine light and I drove home without incident.

Did not drive the Boxster Tuesday or Wednesday because I needed a car with more passenger room.

Thursday October 19 - Drove approximately 25 miles at 65-70 mph top speed. Stopped to buy gas before arriving at work. Put in a very small amount (less than a quart) and the nozzle cut off and gas splashed back from the tank. This is the first time this has happened. Proceeded to fill the tank slowly, and put in a total of 9.1 gallons. I stopped filling as soon as the pump handled clicked off.

The car was extremely difficult to restart. I tried about 8 times. Eventually the car restarted and it ran smoothly – no check engine light.

Like I said, I know I need to leave the car for a thorough diagnosis, but I wonder if anyone has experienced these same symptoms and has any idea what could be causing them.

[insite]

Like I said, I know I need to leave the car for a thorough diagnosis, but I wonder if anyone has experienced these same symptoms and has any idea what could be causing them.

i'm sticking with oil separator; that's my guess.

[KevinH90]

Well, the diagnosis was a "non-functioning evaporative control valve". They replaced the air vent line.

I hope the car stays fixed. It's been an expensive month.