Eng Codes P0300, P0302/6/8 & C1201 5.7 ltr 2013 ??

The truck runs normally, older Son has a good coder-reader. The P0300 = ‘random, multiple cylinder misfires’. The P0302/6/8 identify as ‘misfire detected’ in that cylinder. The C1201 comes up as ‘engine control system malfunction’. One last code, P1604 ‘startability malfunction’.

A net search talks about fuel pressure, air leak, & then ignition problems. The 2013 truck is at about 100k miles. It runs normally, we reset once, came back 5 days later.

The battery is less than a year old, recently checked & charged. I just got involved recently, besides some searching, thought I’d post here. We looked at a few plugs at 80k, left them in since they looked fine. The truck was bought a year ago, plugs may or may not be original.

Since all of a sudden it’s codes on several cylinders, seems larger than individual spark plugs.


Just looking for ideas, thanks.

 

Can you dig into the truck with that scanner to look at the misfire counter? I would want to see if they are just counting up, or if they sit at 0 and don't start counting up unless you drive around.

Which plugs did you look at when your truck had 80K on it?

 

We just took out two plugs near the front, easy ones. This Spring I will change them, could do it earlier. With the sudden, scattered ‘misfire’ codes, thought it would be more broad than spark plug wearing?

The ignition coils come up also as a potential issue. Does one normally change them at some point, preventative?

I’ll try to look into the ‘misfire counter’ issue. I know the engine light did stay off for a while after the 1st reset.

 

My experience with coil packs is that rarely will more than one fail at a time, and when they fail they give a very specific code.

You could swap all the coils in the engine from side to side to see if the misfires change cylinder number, but I doubt that will happen.

How's the rodent situation where you live? If you brought me your truck with all of this information, I would be looking at the wiring harness on the 2, 4, 6, 8 side of the motor and looking for signs of hungry critters.

 

have you done any work on the engine, prior?

I would side with rodents, with the exception that it doesn't do it. last time I got this was my Celica ingesting rain water..... then me messing up my IAC valve, forcing coolant down the intake... Not saying this is you, but something like this can cause a multiple misfire besides wiring damage, grounding, fouled plugs... Have you changed your spark plugs?

 

Thanks. Just done with a net search, about 20 threads & sites about similar issues.

The rodent possibility is low, parked near garage, no cover, I keep ‘bait houses’ in a few places to keep mice at bay.

I have inspected the plugs at 80k, the two I looked at ‘looked ok’. Since we are at 100k now, I plan to change them, regardless.

Here’s some info, this whole event started after we had a strong wind/rain event. The truck is parked outside. Of course the hood was closed, water blown into somewhere? The battery is fairly new, charged up too.

Just for drill I was going to gas up & add some Seafoam later today.

No one has worked on the engine any time recently, or anything else.

 

How old is the fuel?? Maybe bump it up to mid grade for a tank along with the seafoam to bring the octane up... maybe the fuel had a little too much water in it... if you pump gas on base, drop some seafoam on there as well...

 

I will try that when the son gets home, fresh fuel, no ethanol. Right now the misfires are reported on the ‘even side’, last time we reset there was a 5 mixed in, all even currently.

I do agree, with the broad codes(multiple cylinders) it’s not just one spark plug or coil.

 

OK, update. Went for a ride, added non-ethanol fuel(from 1/4 tank) plugged in OBD reader, and 1 can of Seafoam.

First off, the ethanol reading started at 59%, after the fill-up it bounced some, then a fairly steady 45%. Reading on the net, that’s been somewhat common with this flex-engine. ‘Fuel density learning valve reset’, or something similar?

Anyway, just back, doing some research.

OBTW, ‘fuel trims’ were negative initially, then went slightly positive later in the ride, -10 average then +3 average. The negative matches the info on the Toyota SB page I posted.

 

I have a copy of the TSB from Toyota. Right now I’m thinking the ECU thinks the ethanol content is very high. Again, the most we put in is the common 10% ethanol. The web is rife with similar stories.

I’m off to work, a friend has the Techstream cable, IT guy has the program. I sent an email to Toyota central. Right now my idea is to get the ethanol % correct. If your Toyota is funky, check the % ethanol it ‘believes’ is in the fuel with an OBD reader. Still doing some research.

 

Oh, I missed that it was an FFV... yeah, you need a ECU reflash, and possibly a replacement fuel pump.. you might as well have them do both at the same time and resolve your issues once and for all... Nothing shittier than bricking your vehicle on a computer issue and chasing your tail on pretty much nothing you can do mechanically.

 

Yes, this is somewhat of a can of worms. Is the fuel pump really an issue? We had the box off last Summer, pump in the fuel tank?

Right now I was gonna start with getting the ethanol reading in the correct ballpark, ‘ECU reflash’ or whatever. I don’t mind paying a dealer to do so. Is it possible to do it yourself with the tech cable & software, plus an I.T. Person? I had read where one guy had to do it every 3-5000 miles?

Anyway, comes up as more of an issue in cold weather too.

 

Yes, the issue is with the cold weather from what I have seen on this forum.... No need to pay them as it is a TSB, and those usually are free99.. You can do it yourself, but you will still require the reflash as it will still knock it out of service until its resolved, but you do understand that part..... The issue is just the reflash, upgrading it is always a plus in my book, but that's up to you.

 

Just an update, home from a work trip. With 1/2 tank of fuel, filled up again non-ethanol. With that the ethanol ‘reading’ dropped to 23%. That isn’t correct, but much better than the 59% we started with.

The code reader showed no incipient lights or codes. I have the tech cord, next step is to try the home reset, once the program is available, I.T. guy working it.