Codes P0302, P0303 and P300, appeared?

Tiny
XJSHEN
  • MEMBER
  • 2009 HONDA ACCORD
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 161,098 MILES
Produced three codes P0302, P0303, P300, and engine warning lights flashing on the dashboard after engine starting time a little bit longer than usual.

The ignition coil plug 3 was soaked with dirty oil, and outside of the ignition coil plug shell and between body space (chamber) was filled with yellow oil while other chambers were not filled with oil. And spark plug 2 and 3 both were damaged when tested resistance with OBD multi meter.
I want to replace spark plugs 2 and 3, and test and replace ignition coils.
I had replaced spark plugs 2 and 3 twice last year, but it could not work longer that may be becaused by the oil leak at the spark plug chamber?

What the cause of the oil leak on the 3, and how to fix it and to check and fix P3000?

Thanks for your direction and instruction!
Saturday, January 18th, 2025 AT 1:08 PM

11 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,053 POSTS
Hi,

If oil leaks into the spark plug tower, it needs to be resolved first. Otherwise, you will damage a new coil again, causing it to fail.

As far as the codes are concerned, they are specific to cylinders 2 and 3, as I believe you are already aware. The P0300 is a random misfire. I strongly recommend replacing the valve cover gasket and resolving the oil leak issue. At that point, replace the two coils and all of the spark plugs so they are firing the same.

I attached the directions below for replacing the gaskets. Let me know if this helps or if you have other questions.

Take care,

joe

See pics below.
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Saturday, January 18th, 2025 AT 7:22 PM
Tiny
XJSHEN
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  • 227 POSTS
Hi Joe,

Thanks a lot for your nice instructions and recommendations!
I found the leaked oil was very clean light yellow in the outside space of plug 3 well as I indicated on the image on the plug 3, plug 4 well was normal no leak, and the leaked oil was not dirty and no smells, looked like wheel steering oil. Is it possible steering oil can be leaked to the plug chamber? And after replacing the spark 3, no more oil leak on the no.3 plug as well, but code p0303 still popped out.

Questions:
1. Should I disconnect the negative battery terminal?
2. Should I replace all the washers and gasketed?
3. If any special tools are necessary?

After get all the necessary protocols on each procedures and strategies I will start the works.

Again thanks!
Steven
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Monday, January 20th, 2025 AT 2:07 PM
Tiny
XJSHEN
  • MEMBER
  • 227 POSTS
Plug well 3 and 4, and space between plug 3 well shell and engine full with clean non-smell oil, not engine oil, maybe wheel steering oil, but my car oil was dirty than this oil. This was connected with code p0303. The resource and route and name of the oil, is not clear. Is it possible new steering oil leak to spark plug well shell?
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Tuesday, January 21st, 2025 AT 4:54 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,108 POSTS
That's a good one it looks like coolant. Can you confirm that is the same color as your coolant?
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Thursday, January 23rd, 2025 AT 9:19 AM
Tiny
XJSHEN
  • MEMBER
  • 227 POSTS
Thaks a lot Ken! It is you who gave me a lot of help before. Before the p0302 and p0303 was the problem every time with trouble code. No, the coolant color was blue. The source of the leaked oil was from the outside of spark plug well and engine (first tube, very clean and without smell; wheel steering oil (second tube) was dirty; the Honda coolant fluid was blue (third pipette). And engine oil, brake oil, and transmission oils are dirty with smell. If there are additional oil resources on Honda car that could leak to the well?
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Thursday, January 23rd, 2025 AT 10:33 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,108 POSTS
Do you have rats? Could it be rat urine?
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Friday, January 24th, 2025 AT 8:56 AM
Tiny
XJSHEN
  • MEMBER
  • 227 POSTS
No. We don’t have rats in this area. And. The spark plug wells were all closed by cap with screws tightly. And it was absolutely an oil. I want to replace the ignition position sensor and spark plugs separately before opening the cover. What is your recommendation?
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Friday, January 24th, 2025 AT 12:23 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Do you do your own oil changes? I ask because a shop may have caused a mess that got into that spark plug tube. I've seen engines get an oil bath many times. The shop will do its best to clean things up and not tell you. It's just a thought. Also, other than engine oil, there isn't anything that can get in there. Is it staying dry now that you cleaned up things? If it is and you still have a misfire on cylinder 3, switch the coil pack with cylinder 1 and see if the misfire changes cylinders. Something isn't adding up. Like you said, the oil you found looks brand new. Nothing from the power steering or brakes can get in there.

Let us know.

Joe
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Friday, January 24th, 2025 AT 6:09 PM
Tiny
XJSHEN
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I did all repair works by myself so far. If this oil is from out side of car, Inspection procedure in a dealer may messed up problems. That frequently caused codes p0303, p0301, p0302, p0304, and p0335, p0339. After replacement of crankshaft position sensor cleared p0335 and p0339. After replacement spark plugs cleared p03301 and p0304. After that I realized the oils in the out side of well shell. How can I clean up those oils? Should I open gaskets? I need a diagram and image for around structures.
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Saturday, January 25th, 2025 AT 5:12 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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As far as removing the oil, draw out as much as possible with the tester you used. Then, I would take a rag and spray something like brake cleaner on it and then wipe it out as best as I could.

Also, when you have the coil removed, check the rubber boot to see I there are any light gray spots on it which could indicate spark is jumping through the boot. If there is, it needs replaced or you'll end up with a misfire again.

Let me know how things work out for you.

Joe
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Saturday, January 25th, 2025 AT 8:29 PM
Tiny
XJSHEN
  • MEMBER
  • 227 POSTS
I replaced spark plugs for and ignition coils for cylinders 2 and 3. But two codes p0302 and p0303 still appeared and p300 random misfire code was gone, and engine warning light was gone. I disconnected parts, and all were normal after detecting resistance value and connectivity. So, the codes came from other sources except sparks and coils. If there may be connection problems cause the errors?

How should I work on the current situation?

Do the following things? Fuel injectors, vacuum leaks, damaged sensors, compression test?
Thanks a lot for your directions and instructions!
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Friday, February 28th, 2025 AT 2:58 PM

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