ENGINE MISFIRE HELP Vauxhall Corsa 2015 1.4 Petrol

[cam2002_]

Hi all

Hopefully, someone on the off chance reads this and has some mechanic experience.

We have a 2015 1.4 Corsa with the following DTC codes:
P0300 - Engine Misfire Detected
P0138 - HO2S Circuit High Voltage Sensor 2
P2271 - HO2S Signal Stuck Rich Sensor 2

We've carried out a full service. (We understand this has no benefit/help to the codes above, it just needed doing so we did it at the same time)

The main issue we're trying to solve is the "P0300 - Engine Misfire". As of right now, we've replaced the spark plugs and we're experiencing the same issue and code.

I'm going to make the assumption the next logical thing to do would be to replace the Ignition Coil Pack. After some research around car forums, it seems the most logical and does seem like a common issue.

I have a mate who is a mechanic who is more than confident to carry out this work.

If this was your car, and you had the same problems, what would be your process? I appreciate any insight into fixing this vehicle. Thank you!

 

[cam2002_]

I'd just replace the coil pack, it's only £75 & it's a 5 minute DIY job by the looks of it.

Yep. We went with all Bosch filters/spark plugs for the service. Shell Helix HX8 5-30w for the oil.

We've found the £75 Bosch Coil pack you mentioned, so hopefully after swapping it solves it. Fingers crossed it solves the 02 Sensor issue as well. Thank you!

 

[cam2002_]

I'd just replace the coil pack, it's only £75 & it's a 5 minute DIY job by the looks of it.

Do you think once the misfire is solved, the 02 Sensor issue will be solved in your experience?

 

[cam2002_]

I think that once you solve your misfire then the codes won't come back, yeah.

I had the same on an Octavia 2.0 FSI, that was easier to check the cause though as the code for the misfire was more specific in that it identified Cylinder 3 & the coils there are individual so I swapped 2 & 3 and the misfire moved.

It could be an Injector, plug or even something more sinister of course but as most garages would want more than £75 to even look at it the coil is worth a go, if i'm not mistaken it's just 2 bolts and a single electrical connector.

I'll update as soon as we've done the coil pack. Fingers crossed this solves it.

Unfortunately, it just states engine misfire detected. We have no other information. Other than the 02 sensor being stuck Rich as well.

Does the diagnostic tell you which cylinder?

You could take the plugs out, then put the ignition on, be in a dark place and arc the plugs against the engine block you'll see if they are working or not.

I've had a cracked HT lead cover cause that as well, and it was arcing through the crack into the block before going to the plug

That being said if you've already ordered the coil pack, probably easier just to try that now, you also gotta be a bit careful taking plugs out, or more putting them back in because of the low torque required.

As above all of those codes will be related and cleared once you sort the moment misfire.

That sounds promising. It doesn't tell you cylinder unfortunately. Only that there is the misfire detected as well as the 02 sensor issue.

I've ordered a new coil pack and it shouldn't take long to arrive, I'll update here once it's fitted and codes cleared.

Had an almost identical issue with my partners 1.4 Meriva, a new coil pack (one item for all 4 cylinders) cost me about £50 from Euro Car Parts cured the misfire and got rid of the engine warning light - it didn’t clear the Co2 sensor issue which it also had (I’m guessing that’s what your other code is) as we were selling it shortly after I didn’t bother to fix it….

We went for the £75 Bosch option for the coil pack as all of the other items we serviced we did Bosch as well and generally Bosch is quality.

Yeah, the other code is something about an 02 sensor being rich. I think I'm going to order one just in case and return if it isn't used. Did you notice any problems with the car by leaving the code there and not replacing it?

Thank you for your experience

 

[cam2002_]

The misfire caused by the faulty coil pack can make the car run rich, so might go away once changed.

You provide me with hope. I was going to buy an 02 sensor, and return it if not necessary hoping they'd be under £20, but they're 60 for this car. I'll clear codes once fitted and see if it clears.

Misses had the same in her Corsa coilpack solved her misfiring. It was also very simple to replace with just a couple of bolts and a plug from memory.

That is good to know. Do you happen to know if she had a Rich O2 sensor fault as well?

 

[cam2002_]

Not from memory the coilpack seemed to solve the issues she had. We sold it not that long after. If it was me id replace the coilpack and clear all the codes and see if the 02 one comes back. They may be related.

Yeah, that is basically the plan. It's running rich hence fuel not being burnt. So we're in the hopes that it solves it, if not another £60 on a new sensor haha. Good job doing it yourself is cheaper than a garage

 

[cam2002_]

The code for the 02 sensor was still showing when I scanned the car but it made no obvious difference to how it drove , which was noticeably better with the new coil pack.

Perfect, I'll buy one just in case. I appreciate it

 

[cam2002_]

Your most welcome, had we been planning on keeping the car we’d have changed the 02 sensor, as it was already going I didn’t see the point especially given it didn’t seem to affect the way it drove.

That said, I’m guessing come MOT time it could well be an issue so your right to get it changed.

Yeah, something to do with emissions I'd imagine

 

[cam2002_]

Just an update, we have the coil pack and an O2 sensor tomorrow. I'll update this entire post tomorrow with if it's resolved or the next steps, so someone in the future can use this as a guide

 

[cam2002_]

Update - O2 sensor arrived, coil pack did not despite ordering that a day earlier. Will update this as soon as it's all here and let you know if it resolves. Due tomorrow.

 

[cam2002_]

Update - Coil pack was the problem. Car runs like a dream. Will update the original post.

O2 sensor fault has disappeared too

 

[cam2002_]

Update - Few days of driving, the check engine light is back on. We shall investigate.

 

[cam2002_]

Can’t see an 02 sensor being relevant to a faulty coil pack, get that changed also and I think you should be good to go.

Coil pack + Spark plugs + service already been done with codes cleared, and this did solve everything until today.

Yeah, I am hoping this error is just going to be an O2 sensor. Can't check till Saturday, I'll update.

 

[cam2002_]

Aren’t these stick coils? I did one on an 2016 corsa years ago after the coil failed.

Retrace the misfire and try to find it to a specific cylinder by checking plugs for signs of fouling and Rich running. You could’ve replaced the coil for the wrong cylinder which won’t solve it.

The coil pack comes as one; it is not individual. All four were replaced.

The car sounds, drives and runs amazingly now, so I'd put it down to the O2 sensor fault we had before. It's not misfiring or anything - but I need to read codes on OBD2.

 

[cam2002_]

Long delay for update - O2 Sensor PO138 fault. Back on order. So yes, O2 sensor was needed in the end

 

[cam2002_]

The O2 sensor won't have liked the dousing in unburnt fuel. A damned good thrashing down the motorway may heat it up enough to clean it off, but sometimes it doesn't work and they need renewing. Without depressing you a bad misfire can knacker the catalytic converter and if the car has two O2 sensors the one AFTER the cat will show a fault as the cat is no longer working properly. Again a good thrashing sometimes works. Good luck!!

Thanks for the reply. Yeah, that doesn't sound great. Sensor 2 is showing as a fault, so this would be the one AFTER the cat converter. I have a new one on order. I hope the cat converter is still fine - I'll replace the sensor, then make sure it has a blast up and down a dual carriage way and/or a good drive to help resolve it. Thank you!

 

[cam2002_]

cat's are cheaper than I though payed <£300 on bmw 6, last MOT .... when I initially thought it was sensor had been pretty worried I would sheer off the oxygen sensor extracting that,
but your cars not so old so shouldn't be too corroded, nonetheless prep well.

guess you've never looked at/contemplated removing an O2 sensor

e: which were also something like £80 each for me so 2/3 price of a cat

O2 sensor was £60....

It's being fitted tomorrow hopefully, should resolve everything... car should drive fine without replacing it, just with the light but of course would fail MOT so getting it sorted.

 

[cam2002_]

O2 sensor now done - we shall see if any lights come back.