Troubleshoot Engine Codes

[Yoda]

Need some help to resolve a few issues I am having. Here is the run down:
Engine misfires on all cylinders at idle
With car idling and you turn the lights on it idles worst almost dying out.
Hard to start.

Went to Autozone to test battery and alternator reported all good. Disconnected the (-) Terminal with the car running and it did not shut off. However as soon as I turn on my HIDs immediate shut off.:iono:

Engine Codes that were pulled were C1241, P0010 (part replaced but still shows) P0300-304, P0354 (went away after awhile)

Not sure if its a bad ground somewhere or my wiring harness has a short. I did see what looks like an electric burn on the pins of the AM1 fuse but it is not blown:iono:
Open to any possibilities.

[CTScott]

It does sound like a bad ground or bad connection in general. Have you checked the terminals on the two large connectors of the positive battery terminal for corrosion(under the back of the terminal)?

Also, check the ground straps that go from the negative terminal to the engine.

If all of that looks OK, try measuring the battery voltage at various locations around the car (at the battery, in the fuse panel, at the dash power outlet, etc.

If that looks OK, I would pop the ECM out and pop off its cover to see if there is any visible damage.

[Yoda]

I did none of that... Will do tomorrow and report back.
Thanks CT!

[Yoda]

It does sound like a bad ground or bad connection in general. Have you checked the terminals on the two large connectors of the positive battery terminal for corrosion(under the back of the terminal)?

Also, check the ground straps that go from the negative terminal to the engine.

If all of that looks OK, try measuring the battery voltage at various locations around the car (at the battery, in the fuse panel, at the dash power outlet, etc.

If that looks OK, I would pop the ECM out and pop off its cover to see if there is any visible damage.

I am not that savvy with electrical stuff so this may seem like a simple question. How do I measuring the battery voltage at all those spots? I am assuming I am using a multimeter but apart from that total noob mode.:confused:

[CTScott]

I am not that savvy with electrical stuff so this may seem like a simple question. How do I measuring the battery voltage at all those spots? I am assuming I am using a multimeter but apart from that total noob mode.:confused:

Multimeter set to DC voltage mode (and range set to 20 volt range if it is a manual range type). Put the positive (red lead) on the item to measure and the negative (black lead) on a ground point (bare metal under the dash, unpainted bolt head {if the bolt is screwed into metal}, or a white wire with a black stripe on any connector {white/black is always ground on the Yaris}.

[Yoda]

Ok cool. I do see some green corrosion on the positive battery cable. Seems like its wired into the harness tho. sigh. time for a beer break.

[Yoda]

Still unable to find anything but i found this for my error code:
http://www.microimageonline.com/downloads/YARIS/Repair%20Manuals/Brake%20Control.pdf

Going to dive in later and see what I find.
Thanks goes out to Garm for hosting this doc

[cali yaris]

^ welcome. always looking for more PDFs :smile:

[Yoda]

So it looks like the locking tab broke off my Ignition coil caused the multiple misfire. I am about to switch out the connector with another one from my old harness. I had my alternator tested also at Advance Autoparts. They said it tested good but when I took it for a "spirited" drive the volts at idle where 12.1-12.7 with AC on. When I turned on my headlights it dipped to 12.1v and almost stalled. Revved it to 2000rpm and it jumped up to 13.2v. Still have the P0010 after replacing the part. Is it possible the alternator is bad or bad ground?

[CTScott]

So it looks like the locking tab broke off my Ignition coil caused the multiple misfire. I am about to switch out the connector with another one from my old harness. I had my alternator tested also at Advance Autoparts. They said it tested good but when I took it for a "spirited" drive the volts at idle where 12.1-12.7 with AC on. When I turned on my headlights it dipped to 12.1v and almost stalled. Revved it to 2000rpm and it jumped up to 13.2v. Still have the P0010 after replacing the part. Is it possible the alternator is bad or bad ground?

How did they test the alternator? With the engine running you should see over 13V (typically 13.6V at the lowest while idling), and it really should not drop, even with the AC on.

[Yoda]

Took it out and they tested it in the machine.

[CTScott]

Took it out and they tested it in the machine.

It's either bad, or the ground or power connection from it is heavily corroded. The big wire that is bolted under the grey plastic cover is the positive wire, which goes right to the back of the positive battery terminal. The ground is its case contacting the block. So, the ground straps from the block to the negative terminal are what you want to check on that side.

[Yoda]

Looks like the alternator is bad. Gonna get it replaced. I have had my fill of electrical work. Replacing that ignition coil connector was nerve racking. I will stick to my. Thanks for helping me out CT!

[CTScott]

Looks like the alternator is bad. Gonna get it replaced. I have had my fill of electrical work. Replacing that ignition coil connector was nerve racking. I will stick to my. Thanks for helping me out CT!

I have a good alternator for $65 plus shipping if you are interested.