Help with engine codes

[edogg27]

So my check engine light has been on and off for about a year. I decided to go get the codes pulled at my local auto zone. I was womdering if anyone has had these codes or had any advice on how to fix these issues.

The codes are: P1456 and P0507

Autozone said take it to a local shop or better yet a dealer. What do you guys think?

[Towncivilian]

There are no TSBs related to either code, going to the dealer will ensure you waste your money.

P0507 is ISC SYSTEM. Is your idle at 750 RPM +/- 50? If not, check for air intake leaks.

P1456 is EVAP CONTROL SYSTEM. Replace your gas cap with an OEM one to begin with. When you fuel up, do you top off the gas tank or stop at the first click? Do you use at least 91 octane fuel?

[edogg27]

I usually top it off and it has the oem cap. The rpm is around 1000-1200 on idle. Where would i check for leaks. I also run 93 octane

[Towncivilian]

Stop fueling at the first click. Excess fuel enters the charcoal canister when you top off and damages it when you top off. Replace your cap anyway with a new OEM part only, gas caps can go bad.

Check around the airbox and throttle body for cracks or leakage and ensure the hose clamps are on tight. Spray some brake cleaner around the intake with the engine on and see if RPMs flare up - if they do, you have an air intake leak. Also ensure the air filter makes a good seal in the airbox housing. If there are no air intake leaks, perform the three relearn procedures following the steps on page EC-81 of the FSM.

[edogg27]

Ok ill try that. Thanks.

[edogg27]

i changed the gas cap with an oem one from nissan directly and also sprayed brake cleaner around the intake and the rpms were steady unless i hit the filter. so im not sure. i have 2 batteries one for my subs and door amp. do you thing that could cause the higher rpm?

[Towncivilian]

Two batteries shouldn't matter.

No air intake or vacuum leaks doesn't bode well for your P0507 code. The next step is replacement of the ECM, according to the FSM. You may end up needing to go the dealer to fix that code.

The possible cause list for P1456 is a lot lengthier (see page EC-645). I'd check all the EVAP vacuum hoses around the charcoal canister to make sure they're not cracked or loose.

[edogg27]

I sent my truck in to get the seatbelts done by the dealer and they ended up breaking the panel so they kept it all weekend till the new one comes in and i have a loaner jeep through enterprise but when i get it back ill double check all the hoses and worst case take it in. :/ thx town.

[Towncivilian]

Maybe you can find a 2003 ECM at a junkyard or eBay to replace yours with, instead of paying an exorbitant dealer price for a replacement ECM. Or just ignore the code if it's not affecting driveability. If you'd like an exact part number for the ECM, provide your VIN.