P0352 - Coil Pack or Actual Curse?
 

I've never owned a vehicle that I hate as much as this. Ive had nothing but problems since day 3.

Most recently, I'm getting code P0352, indicating missed spark on cylinder 2.

My wife got the CEL for the code while driving freeway speeds under light acceleration. It also had a pending CEL for misfire.

I swapped coils of cylinder 1 and 2, cleared the codes, took it for a drive. It was great until I was sitting in a drive through four about 15 minutes, drove away and while in the parking lot going kes than 15 in 2nd, CEL and engine started to misfire so bad it felt and accounted like rod knock. I shut it off, waited about 5 minutes, turned it back on and drove home. Choose is again P0352.

Ive driven this car about 3k miles and ita the last 100 that I've had this issue, so it seems to be a recent development.

Car has 67k total.

Plugs were done at 40k by a dealership according to carfax.

What's my next step?

Thanks in advance.

Sent from my SM-G960U using Tapatalk

Also, had the recall done 2 months ago. [emoji2369]

Sent from my SM-G960U using Tapatalk

Sell that sick puppy - :iono:


humfrz

"What's the next step?"

The coils run off of 12V power, they need a good ground and a trigger signal from the ECM. Since you've moved the coil around and the issue remained on #2, the next step is checking for good power and ground at the coil. If present, the resistance of the trigger circuit to the ECM,

If everything checks out, you'll have to catch it while it's missing and check everything with the engine live. Leave some backprobes on the connector so you don't have to unplug anything when it starts missing. You won't be able to check the resistance of the IGT circuit while it's running so you'll have to check for an actual signal at the connector, either with a DVOM in DIS RPM mode or a scope, IGT is a 5v square wave, so a scope is ideal, there is an example waveform in the "Terminals of ECM" header near the top of the SFI section. If no IGT at coil check for IGT at ECM connector.

Note: when checking for power and ground and the coil, don't use a DVOM, but a test light with an incandescent bulb so it loads the circuit. many weak connections will go undetected by a DVOM because it doesn't draw power for a circuit. If the light doesn't illuminate brightly or you are unsure, you can either compare to another cylinder or use a DVOM to see the voltage drop from B+ down to that terminal while it's loaded.

Sounds like a pain? It kind of is, at least it's a really simple 3 wire circuit.

https://demos.starbase7.net/t3Portal..._rm_index.html

Engine/Hybrid System > FA20 Engine Control > SFI System > P0351-P0354

The issue deserves to be diagnosed right.

You're a godsend. Thank you sir.

Do you happen to know the pinouts on the connector? Is ground handled by the brass mounting hole and screw to the block, or by the wires? I feel like that's a dumb question, but the oil pressure idiot light ground is the body [emoji849]

...or are these questions answerable in the service manual? I only did a brief search.

Also, this code means theres not really a chance of spark plug failure, right? Its handled by the ignition ECM entirely, right?

Sent from my SM-G960U using Tapatalk

Also, in holistic troubleshooting, the code is still on the same cylinder, but the issue is entirely different. The engine misfires constantly after heating up to temp, whereas before I ****ed around with the connectors and plugs it ran and drove completely normal, other than the CEL - in case that sparks any ideas as to what has happened.

Sent from my SM-G960U using Tapatalk

Ground is a wire in the connector. All 4 cylinders will have the same color ground, same color B+ and one different wire for each, that's the ignition trigger circuit from the ECM. There's also a mini-wiring diagram at the code page that only has the terminal but no colors, coupled with the above knowledge, it should be easy to figure out which is which, but it says B+ is terminal 1, ground is 2 and IGT is 3, there is a diagram at step 2 of the flow chart.

And yeah, as defined the service manual, it's not a plug failure, it's a primary circuit failure, but it never hurts to double check the plug. Since you put the coil on #1, check the plug and if you have no visual cues, put it on #3 and return focus on the primary side of the coil.

Oh and it might seem condescending, but read everything on that trouble code page at the link, even mechanics sometimes try to skim through and get bitten up the bottom by weird issues. Up in the "Terminals of the ECM" section, you're looking for terminal A36-10, the example waveform is no13 further down.

[edit]

As for the issue being different, yeah that's a possibility, start her up and wiggle every connector or bit of wire you touched. If it starts missing you may have shortcutted your way into finding your wonky circuit. Another thing comes to mind: disconnect the coil and using a fine sewing needle, insert it into the terminals of the connector and coming and going, check for proper friction between the needle and terminal. Again, if unsure, compare with a connector from a known-good cylinder, a weak tab inside a connector terminal is a PITA to find and can make life hell.

And you did an excellent job of explaining - :thumbsup:


humfrz

Not condescending at all. Because I'm on mobile. It actually didnt take me directly to that page, but now I see it.
I actually dealt with loose pins on the OBDII port back when I first got this a few months ago. Based on the fact that it worsened just after moving things around I'm convinced the problem is plug-centric, or at least in the wire harness, so I'll look at the pins, then try continuity checks first.

Side question, because of the architecture of the boxer, is it extremely detrimental to run with a misfire?

Sent from my SM-G960U using Tapatalk

Wait a second. Techs are supposed to be 12 year olds who write in crayon and only own a hammer...


Well explained. While I’m not a fan of back probes, you have to do what you have to do when the correct test leads aren’t available. Please please please don’t use the piercing probes. As handy as they are, you’re only inviting corrosion to already delicate contacts.

I’ve always found bad coils to either fail completely, or consistently break up under load. Chafed wires usually come out under heavy throttle, when the engine shifts considerably. Loose sockets will definitely lead you all over, as well as “microcorrosion” or whatever the word of the day is.

Wasn’t there something with loose bolts at the drivers or something along those lines? Possible corrosion there as well. I know the Benz m274 uses the harness mounting bolts as grounds. Loose harness = no start.

Make sure the injector driver or what ever they call it is bolted down all the way. I’ve seen a bunch of people get their car back from the dealer after the recall where the bolts were just finger tight. The car will misfire like crazy if this thing isn’t bolted down all the way. The injector driver is on the left side of the engine when looking into the engine bay. 10mm bolts.

Yeah piercing probes are evil.

I've got tiny little backprobes (Mac ET95923) that are the thinnest and sharpest things around and have a banana plug on their butt to hook directly onto a DVOM or scope lead, they're GREAT.