Clubjazz - Honda Jazz & HR-V Forums
Honda Jazz Forums => Honda Jazz Mk2 2008-2015 => Topic started by: john24 on May 08, 2021, 07:25:20 AM
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Hi everyone,
I need a bit of help. I got a Honda jazz 2010 1.4 iVTEC model. Recently I had a engine warning light pop up when I turned the car on and when driving in went into limp mode and would not go above 30mph. After scanning the car with OBD2 it showed error code saying cylinder 2 had detected a misfire as I haven't changed spark plugs in a while I did a charge them to be iridium ones but sadly the error came back.
To check if it's coils I switched the middle two coils to see if the issue would jump to cylinder two but sadly once again it did not.
What should be my next course of action?
Thank you
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Hi everyone,
I need a bit of help. I got a Honda jazz 2010 1.4 iVTEC model. Recently I had a engine warning light pop up when I turned the car on and when driving in went into limp mode and would not go above 30mph. After scanning the car with OBD2 it showed error code saying cylinder 2 had detected a misfire as I haven't changed spark plugs in a while I did a charge them to be iridium ones but sadly the error came back.
To check if it's coils I switched the middle two coils to see if the issue would jump to cylinder two but sadly once again it did not.
What should be my next course of action?
Thank you
Could be ECU some posters have had ECU ignition outputs go bad.
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Hi everyone,
I need a bit of help. I got a Honda jazz 2010 1.4 iVTEC model. Recently I had a engine warning light pop up when I turned the car on and when driving in went into limp mode and would not go above 30mph. After scanning the car with OBD2 it showed error code saying cylinder 2 had detected a misfire as I haven't changed spark plugs in a while I did a charge them to be iridium ones but sadly the error came back.
To check if it's coils I switched the middle two coils to see if the issue would jump to cylinder two but sadly once again it did not.
What should be my next course of action?
Thank you
Could be ECU some posters have had ECU ignition outputs go bad.
I see, is that the contacts going bad or the ECU itself dying?
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Hi everyone,
I need a bit of help. I got a Honda jazz 2010 1.4 iVTEC model. Recently I had a engine warning light pop up when I turned the car on and when driving in went into limp mode and would not go above 30mph. After scanning the car with OBD2 it showed error code saying cylinder 2 had detected a misfire as I haven't changed spark plugs in a while I did a charge them to be iridium ones but sadly the error came back.
To check if it's coils I switched the middle two coils to see if the issue would jump to cylinder two but sadly once again it did not.
What should be my next course of action?
Thank you
Could be ECU some posters have had ECU ignition outputs go bad.
I see, is that the contacts going bad or the ECU itself dying?
ECU fuel injector solenoid outputs can go bad, not so sure about ignition coil outputs TBH - but if an injector playing up can cause rough running and misfires.
Read this thread
https://clubjazz.org/forum/index.php?topic=10333.msg91051#msg91051
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Could anyone guide me as to where I find the ECU module?
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Could anyone guide me as to where I find the ECU module?
Unless you know what you are doing, leave the ECU alone. One poster had a similar issue. After doing what you have done a garage said it was the EGR and had the EGR cleaned and that cured their problem.
I had a similar problem and after changing plugs and coils it was no better. Then what had been a wuffle from the exhaust developed into a hole and on replacing the front box the warning went away.
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I agree. The problem is normally at the source of the fault, as revealed by the fault codes. Not the computer that detects it. ECU's can go wrong, but needs an expert , and even they might work entirely from plugging specialist equipment into the OBD 2 port, and not touching the ecu itself.
Sorry if the answer sounds flippant, but I have never heard of anyone learning anything from looking at an ecu ,other than its full of water. Also obscures the fact I dont know where it is on a Jazz :-[
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Also obscures the fact I dont know where it is on a Jazz :-[
Me neither. And neither does my mechanic.
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Thanks for the responses guys.
I wanted to check where the ECU was because I would not fix this myself but would have it tested. Some people have reported this issue was caused my the ECU after which sending it off to be repaired also the repaired the issue.
During the summer the fault went away and now in the winter came back. I am now also seeing that the cylinder 4 is also reporting a misfire
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You can never say never, but car ECUs are extremely reliable due to the engineering and testing which goes into them. Unless all other possibilities have been ruled out, the ECU would be last on the list of things to suspect. If a problem is definitely electrical rather than physical, the first things to check are connectors (take apart, spray with contact cleaner, work in/out a few times).
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Could anyone guide me as to where I find the ECU module?
Unless you know what you are doing, leave the ECU alone. One poster had a similar issue. After doing what you have done a garage said it was the EGR and had the EGR cleaned and that cured their problem.
I had a similar problem and after changing plugs and coils it was no better. Then what had been a wuffle from the exhaust developed into a hole and on replacing the front box the warning went away.
Hmmmmm actually now that you mention it, when I sometimes open the door with engine still on I can hear sort of a gurgle as the exhaust pipe was right below me in the middle compared to being at the back. So your issue was a whole in the exhaust ?
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The ECU is on the passenger side, behind and to the right of the battery, mounted vertically
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So your issue was a whole in the exhaust ?
Two holes actually. Where the bracket ahead of the middle box is welded onto the pipe. I think it was close enough to the rear O2 sensor on the cat that it was causing the sensor to give duff information.
(https://i.ebayimg.com/thumbs/images/g/DZcAAOSwNSxVZMbn/s-l300.jpg)
Bracket about 8 inches to the right of the box in this photo.
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Thanks Jocko, I will have a look at my exhaust.
What's odd is that you can't feel missire when driving, and I've had misfires on other cars and I could 100% tell that a cylinder is misfiring.
Sometimes I will start the car and it will be a bit rough, a VSA light will come on sometimes. I then turn the engine off and turn it back on and all's good, the car runs smooths and has no issues apart the check engine light being on.
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That was exactly the same as mine. Running smooth but telling me I had a misfire (and sometimes on more than one cylinder). Sometimes the MIL would flash for a few seconds and other times it would come on and stay on. I would reset it from my ScanGauge and sometimes it would do it more than once on one 40 mile trip.
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My first thought was wouldnt a hole in the exhaust that affects the 02 lamda sensor throw up a code for that, not a misfire on a specific cylinder.
But on further thought maybe the ECU is trying to bring the exhaust 02 levels ( an indicator that the engine is running efficiently) back to normal by changing engine settings, for instance by changing the fuel/air mixture . In which case the first reading that causes a fault code may be when one of the cylinders starts to misfire slightly because its getting the wrong fuel/air mix. But the changes may mean the 02 sensor will be getting the correct levels, so doesnt show its own fault code.
May be of no help, and sorry if I am stating the obvious :-[
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All's good thank you, the more I have to go on the more I can check :)
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So I checked the exhaust and looks new no leaks or holes that I can see or hear.
I checked the EGR valve and it seems good and the valve is moving freely.
On the first start car runs rough I found that if I clear the error codes and start it up again it runs smooth again
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You say you have read the OBD11 code(s) and cleared it (them) but it is only a temporary fix.
I presume this is a generic code (which covers any number of faults rather than a specific Honda code)? If you post up the code you have maybe someone will be more able to identify possible components to check.
Alternatively, it may be worth the cost to have the car scanned with a Honda scanner to closer identify the possible faulty component (rather than the fault).
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Fair point the OBD-II code I get is: P0302: Cylinder 2 → Misfire Detected
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So I had the ECU sent off for testing and it came back as all clear and no issues. So that can be ruled out as well.
What should be my next things to test?
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Members will help if you provide further info-
What happened/changed before the fault appeared?
When was the Jazz last serviced, when plugs changed?
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What have you done to cure the cylinder2 misfire? Clearing the fault code doesn't fix the problem. Is it still flagging the same fault?
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I am pleased to say that since replacing the leaky exhaust I have had no reoccurrence of P0302. So after changing plugs and coil pack made no difference, I am delighted with that result.
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Members will help if you provide further info-
What happened/changed before the fault appeared?
When was the Jazz last serviced, when plugs changed?
Nothing, the car just one cold morning poped up with check engine and VSA light and ran rather rough, would not change gears properly. After being turned off and then on again would run much better. Car has always been serviced at appropriate intervals. Spark plugs are essentially new as I had them changed once the issue appeared.
What have you done to cure the cylinder2 misfire? Clearing the fault code doesn't fix the problem. Is it still flagging the same fault?
I changed spark plugs and checked the EGR valve. I swapped the coils to see if the issue would jump cylinders but it did not. I also had the ECU tested for any malfunctions.
I am pleased to say that since replacing the leaky exhaust I have had no reoccurrence of P0302. So after changing plugs and coil pack made no difference, I am delighted with that result.
Was the leak obvious? or was it something really small? Also where to the in the exhaust was the leak?
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Was the leak obvious? or was it something really small? Also where to the in the exhaust was the leak?
Initially the leak was tiny. I didn't even realise I had a leak. It was a tiny break at the weld ahead of the middlebox (the one under the sill) where the mounting bracket attaches to the pipe. At no time did I notice or feel any symptoms. I would just reset the code (I could do it on the go from my ScanGauge) and that would be it for a couple of days, sometimes only for a couple of miles. Seemed to always do it on a trailing throttle, like slowing down for a roundabout or on a steepish descent.
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So I got under the car again to check for the exhaust leak. I had a mate for a price of cloth over the exhaust to see if it helps at the front to make things more obvious būti find nothing. However the error on the dash went away for 2 days then came back. I tried the same trick again but that didn't work.
I think I'll test the cylinder compression next to rule that out
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Any updates?
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I just got the cylinder compression test kit and will try to test it this weekend.
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So the compression results are as follows:
C1:175psi
C2:125Psi
C3:160Psi
C4:175Psi
So cylinder 2 is low indeed, but it does not explain why the error shows misfire on cylinder 4 as well.