2010 Donation Program Prius: TCS light (C1231 on snapon) and random misfire (3/4)

Hi Folks,

Back with another donation prius to work through.

Got a 2010 Prius, 156k on the ODO, overall pretty clean and drives well. Two discovered issues:

Random misfire on cold start, when it happens knocks for a bit then goes away. Not losing any coolant over the three days I've been driving it so far, changed the oil upon receipt and the oil is still just oil (no chocolate milk on the dip stick). Haven't ripped apart the wiper area to get to the plugs yet, but I would assume they're original. Once it said misfire on cylinder 4 alone, most recent one was cylinder 3 and 4. I was, however, able to get it to pass smog test in California (drove it yesterday, CEL came up with cylinder 4, reset and drove around today, was ready to smog, smogged it and it didn't misfire again until...)

Also, the car came with the traction control light on. I was at the shop that helps us out with donation cars (did the smog there) and after the smog I plugged in the shop's snap on scanner. Came back with code C1231. Attempted to reset with the snap on, TCS light still on. Drove home, unplugged the 12v battery for 30 mins, TCS light still on. To add to that, the vehicle ran rough after hooking the battery back up and turning the car on, CEL right away. No other brake lights on (ABS, brake light, right side of the dash, etc), only the left side TCS/VSC light with the picture of the skidding car on.

Coil pack wiring looks fine. My assumption is: remove wiper assemble and platform and replace plugs for the misfire. Maybe replace two coil packs? Denso iridium, right?

Regarding C1231, do I need a techstream to work on it (get the steering wheel readings, align, etc)?

Thanks!

 

Thanks for all the replies. Planning to work on the car tomorrow (need to rent the compression test set from autozone to test all the cylinders, need to change the plugs, and need check out the EGR pipe).

 

Thanks for this. I found an old Android phone and actually found the BAFX OBDII reader (someone had left it in a previous donation car, I just tossed it in my toolbox to save it for later).

Will get the readings and report back tomorrow

 

Thanks, will look. Is it visible enough to see w/o one of those port cameras?

 

Didn't get a chance to remove the wipers and inspect the cylinder yesterday, hopefully soon.

I did hook up the BAFX OBDII with Prius Doctor, no hybrid codes.

 

Aren't GIFs required when posting meme style comments?

 

....and I'm back.

Finally got around to removing everything to inspect each cylinder and check the plugs.

Plugs were fine, just old (looked worn, maybe the ones from the factory). Had to ask the neighbor for a pen flashlight.

Thankfully, all 4 cylinders looked equally "dirty" with carbon build up from combustion. Nothing looked clean or had clean spots from coolant dripping through. Oil on the dip stick was still clean, no chocolate milk.

Put in new plugs, drove around, car appears to hum better than before. Will continue to drive around to determine if this has fixed that problem.

TCS light on the left side still on. No hybrid codes (using Dr Prius and an android phone), no engine codes. Any advice on trouble shooting this?

Thanks again for all the help!

 

Thanks for the reminder (since you did mention it above). Will remove and inspect/clean in the next few days. Hoping to finish this car by the weekend and have it ready to hand off.

Might as well clean the intake and the EGR pipe in one go.

 

Got to it today: Looks fairly clean, no blockage, cleaned out very easily, etc..

Drive it around for a week and see if the misfire comes back.

TCS light is still on, need to figure this out still.

Thanks!