2005, 245K miles, gets about 45mpg, reliable, daily runner: every 5 months or so the ice will run rough and may throw a P0304 code. I run a can of Amsoil Deep Creep through the manifold and work a local hill climb and that will clean up the misfire and the code, temporarily. P0304 points to #4 cylinder so I replaced that original coil along with all 4 spark plugs. She started up, ran fine but in a few miles, red triangle, P0354 code, no ICE. Pulled over. Checked all the coil connections and the wiring harness (looks like it sounds). Would power up and ICE would start up, sputter, quit. AAA towed back to my driveway safely. Any helpful thoughts, recommendations are appreciated in advance. Posted via the PriusChat mobile app.
My first thought is if you replaced some parts after which things got worse, then maybe the part you installed is bad. Can happen. I have pretty much given up on most aftermarket brands due to unknown quality. For Toyota I prefer OE or Denso (the OE supplier). On some of these year Toyotas the ecm will shut down the fuel injectors if it doesn't get a good feedback signal from each coil. One thing to keep in mind is the state of charge left in your hv battery. Everytime you try to start the engine that will use up more juice and eventually you will be stuck with a discharged hv battery. Very few people have a means to recharge it so that would be game over. Also be aware that when the prius tries to start it spins the ICE at 1000 rpm for several seconds, so what sounds like a start and stall, might really be a crank-no start. Posted via the PriusChat mobile app.
Ugh. So the discharged hv battery just moved to first position. Your sequence makes perfect sense: multiple starts totally discharge the hv, game over. This car was running great, perfectly reliable b4 I changed spark plugs and the one coil (P0304). What a bummer. Posted via the PriusChat mobile app.
Yes, DENSO OE coil but I hear those can be counterfeit too. I may throw the old coil back in there and see what happens. She was running before fine. Posted via the PriusChat mobile app.
What I would do is test the harness and coil with a voltmeter and associated sensors. Cam position sensor, etc. Here is the link for the GenII repair manual. There are instructions to troubleshoot and the specs for the harness at the coils given in the document. https://drive.google.com/drive/u/0/folders/0B7FYqTrI8SS6QTA1RW5Yd3hpTUU
Update: I slept on this problem for more than one night but a solution did come eventually. I reinstalled the old coil, cleared the codes and took the risk of starting it up again. It was at the last absolute pink bar so I was completely concerned that I might discharge the HV battery to 0 and be in a fix. She started after the code clearing and ran long enough to give me hope. I ran the codes again and it pointed to the MAF sensor although I forget that code now. Anyway, I removed the MAF sensor (two Phillips screws), sprayed a good 10 sec stream of MAF cleaner, waited a min, reinstalled and CAR STARTED UP, ICE CHARGED UP TO FULL GREEN, RUNNING GREAT FOR WEEKS NOW. Moral of the story: start with the MAF cleaning and NEVER GIVE UP. Posted via the PriusChat mobile app.
When you used cleaner on your MAF, did you shoot it inside at the two little sensor resistors? Hard to see if you don't know that they are there. Posted via the PriusChat mobile app.
Unfortunately it's the end of the road for this old girl. She saved my son's skin as her final act though. Thank you Toyota for being crazy enough to create this magnificent vehicle. Posted via the PriusChat mobile app.
i just got same code - not really mechanically inclined car wise but can do simple things after an explanation video. Are you saying that cleaning the maf sensor was the culprit and that too care of the problem? Do you have vid or sourse to look at how its done (will check ytube) also do you rteset code or once fixed will code reset on its own.
Please forgive me for checking to make sure, but are you saying you literally got the same two codes, P0304 and P0354? P0304 is a generic code indicating that the engine is misfiring in cylinder 4 for some reason. You'd be missing the point if you read somebody else's thread where the reason for them turned out to be the MAF sensor and expected that to mean your car has the same problem. The point with a P0304 is you have to find out why your engine is misfiring there, and then fix that. Fuel, compression, and spark are the main things to check. If you really do also have the P0354 code, that indicates a problem with an ignition coil. Most likely #4, but the ignition feedback circuit is shared by all four, so on rare occasions weirder things can happen.
no just the p3034 code as of wed this week but for the las 3 months the mpgs dropped from about 45 to 40.
no just the p3034 code as of wed this week but for the las 3 months the mpgs dropped from about 45 to 40.
