filled up gas tank and p0420 code came on

jnsn
0

Asked by jnsn May 05, 2014 at 11:11 PM about the 2003 Pontiac Grand Prix SE

Question type: Maintenance & Repair

2 Answers

Norm Davis
3,125

P0420 code (Catalytic Converter) can be generated by any number of sensors upstream of the converter. More than likely there is a problem with the evap recovery system or the valve that's supposed to prevent over-filling the tank. When this happens, excess gas fumes are drawn into the engine (as it should) causing a rich condition, which triggers the Cat sensor to throw the P0420 code. Get the tank filler pipe and evap system checked out. There is probably one or more other codes being thrown, check the entire system.

2 out of 2 people think this is helpful.
Mechchic
10

You may just have a loose gas cap. When I worked in parts, I had that code and complaint all the time and 95% of the time it was cause of a loose gas cap.

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

Grand Prix
Looking for a Used Grand Prix in your area?
CarGurus has 3,924 nationwide Grand Prix listings starting at $1,900.
ZIP:

Search Pontiac Grand Prix Questions

Pontiac Grand Prix Experts

#1 Js08016
Js08016
Reputation 2,140
#2 Tom Demyan
Tom Demyan
Reputation 1,680
#3 John Saffrahn
John Saffrahn
Reputation 1,120
View All

Related Models For Sale

Used Chevrolet Impala"
1,310 Great Deals out of 56,362 listings starting at $884
Used Pontiac Grand Am"
27 Great Deals out of 1,839 listings starting at $750
Used Chevrolet Monte Carlo"
48 Great Deals out of 1,773 listings starting at $1,999
Used Pontiac Bonneville"
18 Great Deals out of 732 listings starting at $995
Used Ford Mustang"
667 Great Deals out of 33,495 listings starting at $1,950
Used Chevrolet Malibu"
1,118 Great Deals out of 58,477 listings starting at $800
Used Chevrolet Camaro"
484 Great Deals out of 34,165 listings starting at $1,595
Used Pontiac GTO"
4 Great Deals out of 287 listings starting at $7,988
Used Honda Accord"
1,221 Great Deals out of 61,826 listings starting at $899
Used Nissan Maxima"
478 Great Deals out of 13,518 listings starting at $1,495
Used Nissan Altima"
1,613 Great Deals out of 84,312 listings starting at $551

Used Cars For Sale

2008 Pontiac Grand Prix For Sale
19 Great Deals out of 541 listings starting at $3,295
2007 Pontiac Grand Prix For Sale
32 Great Deals out of 527 listings starting at $2,995
2006 Pontiac Grand Prix For Sale
26 Great Deals out of 607 listings starting at $1,900
2005 Pontiac Grand Prix For Sale
20 Great Deals out of 455 listings starting at $2,495
2004 Pontiac Grand Prix For Sale
27 Great Deals out of 619 listings starting at $1,987