I got a P1259 and P0401. Engine check light came on yesterday 10 minutes after buying a full tank of gas from a shady looking station in the middle of nowhere. Not sure if gas has anything to do with it, but thought i'd mention the shady looking station. Its off of exit 144 on I65. The pumps dont even take credit cards...

Anyways, I got a 99 Accord EX 4cyl.

Can anyone direct me to an online service manual? or help me out with these codes. Would greatly appreciate it!

 

P0401 is Exhaust Gas Recirculation (EGR) Insufficient Flow

My guess would be clogged EGR ports. The valve may just need to be cleaned, so I would not just go out and buy an EGR Valve. There is a way to test it, I'm sure but I don't know right off hand. I would have to look it up. Good luck

I didn't find the code for P1259

 

P1259 may, or may not be VTEC system malfunction.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BLKFLSH &raquo;</TD></TR><TR><TD CLASS="quote">P1259 may, or may not be VTEC system malfunction.</TD></TR></TABLE>

Correct it is the Vtec solenoid code, always check the oil level when you get this code.
P0401 is an emission code so it takes 2 drive cycles for that code to appear, meaning it had nothing to do with the suspected gas station.

I think you owe the folks at that gas station an apology. LOL

 

ok, so 2 drive cycles means drive, turn off vehicle, then drive again right?
Which code came first? can one be the cause of the other? I dont see any relation between the codes. What does EGR valve have to do with VTEC? I'm not 100% clear on how the vtec works, but I know that its oil pressure driven. When the oil pressure reaches a certain level, due to RPMs, it trggers an extra cam or valve to open. exhaust valve or intake valve? i dont know?

Anyways, more importantly, whats the easiest way to reset those codes? unplug battery or pull a fuse? push the dash buttons in a particular way? I think it would be a good idea to see if the code triggers were accidental or are really a problem.

Does anyone know more specifics about code P0401? what part of the vtec is malfunctioning? What about the EGR valve, where is that located? catalyc converter?

I'm so used to working on simple motorcycles that arent tightly governed by emissions regulations...

thanks for all the help fellow brothers!

 

BLKfish,

How does the ECU measure flow through the EGR valve? is there some pressure sensor tha relates pressure to RPM and deduces volumentric flow?

 

according to the list of all OBD2 codes i have in my hand P0401 says exactly: "Exhaust Gas Recirculation Flow Insufficient Detected"

 

I agree with HondaDude.. Everytime I've seen that VTEC malfunction code, I've sent customers home with a $100 oil change.. I'd definitely check the oil level first. I believe the system doesn't work if you're a quart low. As for the EGR code, you seem lost. Just take it to the dealer..

 

The 2 codes are not related to each other; 2 seperate problems, as far as the "low flow" there is not a flow sensor per say. the ECU knows when it commands the EGR valve to open and expects to see certain amount of change on the primary O2 sensor.
You'll need to split open the throttle body and clean the carbon build up out of the big hole where the Exhaust Gas Recirculates into the intake, also rod out the passage going back toward the EGR valve, then blow it out with compressed air.

 

yeah, i just did a 900 mi drive down to the gulf coast and back. oil was low when i left, added some but it wasnt up to the high mark. just checked it today, 500mi later, and it was 5mm or so below the low mark. thats probably why the vtec light went on.

i'll tear open the throttle body tomorrow and clean it up... guess i'l have to break out my parts cleaner that hasnt been used in a few months.

thanks for the info. i'll keep you all posted.

btw, how do you reset the codes if possible without disconnecting the battery?

 

There should be a fuse to pull. Don't know which one on a 99 Accord. If you are going to disconnect the battery, make sure you have the radio code first.

 

yeah, i just did a 900 mi drive down to the gulf coast and back. oil was low when i left, added some but it wasnt up to the high mark. just checked it today, 500mi later, and it was 5mm or so below the low mark. thats probably why the vtec light went on.

i'll tear open the throttle body tomorrow and clean it up... guess i'l have to break out my parts cleaner that hasnt been used in a few months.

thanks for the info. i'll keep you all posted.

btw, how do you reset the codes if possible without disconnecting the battery?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BLKFLSH &raquo;</TD></TR><TR><TD CLASS="quote">There should be a fuse to pull. Don't know which one on a 99 Accord... </TD></TR></TABLE>Open the right-front door, there's a fusebox in that end of the dashboard. It's #13 in there.