P0492 Code - aaargh! MODIFIED CODE

C

Courageous

Member
Hi guys, engine management light on and used my code reader. It gives one code only P0490. Clear the code, warning light extinguishes and returns some 30 miles later.

Car is an e85 2.0 year 05.

Anyone been here before?

Modified the post to reflect the ACTUAL code P0492
 
Ok, cuppla questions since I don't have an owners manual:

1) Does anyone have one for a 2.0 E85 year 05 in PDF format please?
2) In the absence of this - when does the EML light come on? At the moment I only have the image of a yellow engine with this code so am wondering if it has to be a more serious code to bring on the EML as well.
 
Thanks ph001 - that description didn't ring bells to my fault and have now modified the title to read P0492 - secondary air. Have read up on internet and found some videos and descriptions but nothing specific to Z4. Will try another search for P0492 and see what pops up here.

Ian
 
Thing is it ran fine for the 1200 km or so from UK to Catalunya and no code - since arriving and doing 20 mile runs to work daily it's returning every second trip. Looks like I'm going to have to get down and dirty and buy a vacuum test kit.......
 
The secondary air injection is probably emissions related - a very common problem with the 2.0l engines unfortunately which nobody has ever really got to the bottom of I don't think (apart from cracked manifolds) .... https://z4-forum.com/forum/viewtopic.php?f=3&t=103895&p=1519517&hilit=emissions#p1519517
 
Check the fuel tank seal, also does it happen when you go from low fuel to fill up? Had this on the Z3. It was seal on filler cap. Went on it's own.
 
Thanks Coupster, it's hard to say what's triggering it as it happens regularly. My commute is approx 20 miles. If I reset the code I can drive to work, drive home, go to work again and it happens half way home so say every 70 miles. Like this I can probably reset the code two or three times per fill. Will look at the seal though.
 
Ok took a look at the gas cap and this is the situation. Would this perishing be the cause? Anyone check against their own for a comparison please?Gas cap.jpeg
 
That could well be the problem. It affects the EVAP system. It's got to worth a change, or find something similar to try.
 
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