Archived Check engine light on no code in window

[ABarry]

Hey, I have and 06 mega and today the check engine light came on when I went to start it. I cycled the key 3 times and no codes come up just says --done--.

I did put a locking gas cap on about 30 miles ago. I got it from genos and it seems to fit and work right. Any thoughts.

 

[WKruger]

Don't believe the diesels will throw a code for leaving the fuel cap off, or when you run a different one. Run down to a parts store and see if they can scan for codes.

 

[Missouri Mule]

The check engine light probably has to do with something when starting up (starting system).

If you had the cap on for thirty miles I doubt it is the problem, if the cap isn't on tight enough or messed up with the tank at a 1/2 or less it could set a code.

 

[ABarry]

I had the CEL come on with a Isuzu rodeo if the cap was not on right, thats the only reason I bring it up and its the only thing different on the truck. I put the stock cap back on will see what happens. Thanks for the replys. I will give the parts store a try.

 

[Missouri Mule]

You mite need a code reader to get the codes.

 

[DeezelDood]

Have had same experience. Unable get a code with the key method. Light disappeared after a few start and warm up cycles. Has happed two or three times since. Truck ran fine all the while, nusiance indication. Do some searches on this subject, try "CEL" and "code". Many good posts from knowledgeable members. I haven't given this issue, on my truck, a second thought.

 

[ABarry]

Light still on after 5 or 6 trips. Guess I am taking to the dealer. A**holes at the dealer said the need the truck for 1 hour to read the code. No wonder there going under.

 

[ABarry]

Borrowed a code reader P0191???

 

[RRees]

In my 2006 manual it is



P0191-FUEL RAIL PRESSURE SENSOR

PERFORMANCE. . .

² When Monitored:

At key on.

² Set Condition:

The fuel pressure sensor reading at key on does not match the expected fuel pressure reading at key on.

Possible Causes

OTHER DTC'S PRESENT

FUEL RAIL PRESSURE SENSOR

FUEL SYSTEM TAMPERING

INTERMITTENT CONDITION

 

[ABarry]

Fuel system tampering?? could that be the fuel cap you think??

 

[Missouri Mule]

I doubt it. If it was the cap (incorrect psi for your year) it would of set off the cel alot earlier. As long as the tank is close to being full you have enough pressure as the tank goes below almost(3/4 tank full you need pressure in the tank.



On my 96 it was either 25-26 psi fuel cap I don't think it would of changed through the years but you can check. I been you using a aftermarket fuel cap for years. You can try putting the old cap back on.



I would say your fue rail pressure sensor is messing up or your cp3 isn't putting enough fuel into the rail, fca could be going, lift pump going or not puttting out enough fule because cap is wrong psi.

 

[ABarry]

They flashed and we will see. I put the old cap back on.