2001 Accord cel codes P1259 and P0303
 

I have a 2001 Accord 2.3 ULEV VTEC and I have a cel that has come on and sometimes blinked recently and I've experienced a rough idle on it so I ran a diagnostics test on it with my obd II and received the codes P1259(VTEC malfunction) and P0303(cylinder 3 misfire). I was wondering what I should do as far as fixing this problem as I do not want to cause damage to the engine.

Thanks,
Tim

P1259 check oil level. P0303 could be a bad spark plug, bad spark plug wire, bad fuel injector, or low compression in #3 cylinder. You could swap out 1 at a time from another cylinder spark plug, wire, injector and see if code changes. If it doesn't then do a compression check and a leak down check.

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Now I have replaced my sparkplugs a few days ago and today the cel started blinking again so I pulled out the OBD II and scanned it. Now I got the same 2 codes as before but also the codes p0301, p0300, and P1399. What should try next as far as fixing this problem? Will a valve adjustment help? Should I check to see if the timings off? Should I clean my egr port and replace the valve? Should I check the head gasket? Or would compression prove to be the cause? Any responses will help.

Thanks,
Tim

Ok spark plugs are good. Did you check that are getting spark? This will rule out a bad spark plug wire. Also check fuel injectors. You should be able to hear them clicking as the engine is running. Also check for a vacuum leak. If you are getting spark and fuel next do a compression check. See if a cylinder has low compression. If you have low compression a leak down check will help narrow it down.

Valve adjustment or head gasket could cause misfire, but the compression and leak down check should identify this.

Did you check your oil level for P1259?

Thanks for the reply! Most likely I will do a compression test this weekend to see if I have low compression or "hopefully" rule compression out completely and vacuum test will be done. I hear the clicking from the injectors when the car is running but I should probably run some injector cleaner through them. The spark plug wires look to be almost new so I doubt it could be that but then again who knows. If I rule out compression and any vacuum leaks then I will go after the wires. I'm not so sure about the VTEC malfunction code because I've run low on oil before due to a leak in the distributor that I fixed a month ago and oil levels have been fine since. Could it be that it is an old code or would it be related to the misfires in any way, shape, or form?

Thanks for the quick response,
Tim

I would focus on the p1259. The misfire codes are kind of generic.

Clear the codes with your reader. Drive the car until it is warmed up, then drive at an rpm of over 4K for more than two seconds. Does the check engine light turn on?

Check the electrical connectors on for vtec on the passenger side of the cylinder head. Have you done any work in that area of the engine? Did you do any work not long before you got the CEL?

I drove the car and I had it above 4 grand for lets say about 5 seconds in 3rd (auto) and the cel came on and shortly after that and when ever I revved the car over 3.5 grand it misfired. I've replaced the distributor a month ago which is right in front of the VTEC solenoid but this code and problem has been around for about a year. With the leaking distributor it lost a lot of oil so whenever it was low it misfired but I always believed that it was just that the engine was limiting itself so the VTEC would not engage if I had low oil pressure. What should I do about this first since it seems like there is a lot to be checked and which should I pursue, the VTEC system or the misfires? It seems like when driving the car they are related. Just a few days ago the cel started blinking so I decided to take action on this since the car ran fine till this problem started to occur. Also a few days ago the car would not crank or make any noise when I tried to start it and it took me a few times to actually start the car but it has not done it since that one day. I believe it was the immobilizer. Would this have anything to do with the problem I am having or could this be totally different. I thought I might as well lay all the cards on the table so I can get the the bottom of what's really happening. The car has been great with no real trouble till just recently when all the misfires started to happen. I appreciate all the replies as well as any help you can give me.:)

Thanks,
Tim

Sounds like two problems. The no start is due to the starter system.

The vtec code is where I would start.

The next step is to unplug the pressure switch (a two pin connector). Use a volt meter to check for open or closed circuit between the two pins on the electrical connector.

The next step is to check for voltage between the blu/blk wire and ground on the electrical connector with the ignition switch turned to the II position.

Step 3 is to check for voltage between the blu/blk wire and the other wire on the electrical connector.

Let us know what you find.

The thing is, what does this have to do with the misfires? Today I was out in the car and it was really pretty damn rough. Whenever I come to a stop and then let off the brake right before I step on the gas the car feels like it is at 500 rpm but it is actually at 900. I'm going to do a valve adjustment over the weekend and check the timing as well. I am almost positive that this it the problem that I am having. Also when I turned the car on once it sounded like something was scratching against something else. I need a new power steering pump because mine is shot after my pressure hose leak but the noise could be anything. And are you positive that that's the starter? It did it once again today but after trying to start it twice it cranked and turned over. I will tackle the VTEC later because without it misfiring at 3500 I hear it has engaged when compared to the sound of the F23A5(non-VTEC) my F23A4(ULEV VTEC) it sound completely different. Thanks once again for the reply. I truly appreciate it!

Thanks,
Tim