Code P0300....
Thread Starter
Junior Member
Joined: Mar 2007
Posts: 35
Code P0300....
Hey Guys,
This is my first thread on Maxima.org and I need some help. I own a 99 SE Limited Maxima. I have had it since June 2003 and have loved it. At about 125k I had to replace the EGR. The sensor was completely shot and all the airways connecting it were pretty clogged and nasty. It was also about this time that I started getting this random cylinder misfire code off my ECU. It would stay on a few days and then be gone for like a week. At the time, I didn't know a whole lot about cars and just didn't worry about it.
Now it has about 187k miles on it and it stays on constantly. I have replaced the spark plugs, checked the coil packs but that is about it. I don't smell anything unusual on the exhaust so I don't think that it's the cat. At this point I can't take much of the car apart because it is mine and my wife's only car.
Other symptoms that car displays is that it is hard to start, it's sluggish on acceleration, and in the last 10k I can feel the cylinder's missing. I was wondering if there are any quick test that I can run that wouldn't require me to take too much apart?
Thanks for all your help,
JC
This is my first thread on Maxima.org and I need some help. I own a 99 SE Limited Maxima. I have had it since June 2003 and have loved it. At about 125k I had to replace the EGR. The sensor was completely shot and all the airways connecting it were pretty clogged and nasty. It was also about this time that I started getting this random cylinder misfire code off my ECU. It would stay on a few days and then be gone for like a week. At the time, I didn't know a whole lot about cars and just didn't worry about it.
Now it has about 187k miles on it and it stays on constantly. I have replaced the spark plugs, checked the coil packs but that is about it. I don't smell anything unusual on the exhaust so I don't think that it's the cat. At this point I can't take much of the car apart because it is mine and my wife's only car.
Other symptoms that car displays is that it is hard to start, it's sluggish on acceleration, and in the last 10k I can feel the cylinder's missing. I was wondering if there are any quick test that I can run that wouldn't require me to take too much apart?
Thanks for all your help,
JC
This is a confusing welter of symptoms which might arise from multiple malfunctions. It's not a pretty picture.
Possible Problem #1...
Your engine may have been flooded. This caused hard starting and when the engine did finally start it was running rich. The rich mixture caused the engine to run poorly, triggering the Diagnostic Trouble Code 0701. The engine generated a lot of black soot which collected on the sensing element of the Left Bank Oxygen Sensor, rendering it useless and triggering Diagnostic Trouble Code 0303.
You may test this "flooded engine" theory by cranking the engine with the gas pedal pressed all the way to the floor. Cranking with Wide Open Throttle is a signal to the Engine Control Module to "clear a flooded engine". If this technique gets the engine to run you will want to figure out why the engine got flooded in the first place. Possible causes of a flooded engine include
- fuel injectors which stick open
- bad fuel pressure regulator
- obstructed fuel return line
If you are lucky the Oxygen Sensor will recover spontaneously. If not you will have to remove the Oxygen Sensor and replace or rejuvenate it. I have read that an Oxygen Sensor may sometimes be rejuventated by clamping it in a vise and heating the sensing tip red hot with a propane torch. This is said to burn away the crust of deposits which prevents the sensor from working. I have never tried this trick, so cannot vouch for its effectiveness. If your sensor is already "dead" there isn't much to lose.
Possible Problem #2...
You identified DTC 0101 as "upstream oxygen sensor heater or circuit fault." Please double-check this number. My book says DTC 0101 is caused by the Camshaft Position Sensor (Phase). This sensor is located on the engine front cover facing the camshaft sprocket. It detects the cylinder number signal. The Engine Control Module uses this signal to control spark plug firing order and also to sequence the fuel injectors correctly. If the CPS is bad the ECM will fire the plugs at the wrong time, or not fire them at all. This would account for a no-fire symptom.
Possible Problem #1...
Your engine may have been flooded. This caused hard starting and when the engine did finally start it was running rich. The rich mixture caused the engine to run poorly, triggering the Diagnostic Trouble Code 0701. The engine generated a lot of black soot which collected on the sensing element of the Left Bank Oxygen Sensor, rendering it useless and triggering Diagnostic Trouble Code 0303.
You may test this "flooded engine" theory by cranking the engine with the gas pedal pressed all the way to the floor. Cranking with Wide Open Throttle is a signal to the Engine Control Module to "clear a flooded engine". If this technique gets the engine to run you will want to figure out why the engine got flooded in the first place. Possible causes of a flooded engine include
- fuel injectors which stick open
- bad fuel pressure regulator
- obstructed fuel return line
If you are lucky the Oxygen Sensor will recover spontaneously. If not you will have to remove the Oxygen Sensor and replace or rejuvenate it. I have read that an Oxygen Sensor may sometimes be rejuventated by clamping it in a vise and heating the sensing tip red hot with a propane torch. This is said to burn away the crust of deposits which prevents the sensor from working. I have never tried this trick, so cannot vouch for its effectiveness. If your sensor is already "dead" there isn't much to lose.
Possible Problem #2...
You identified DTC 0101 as "upstream oxygen sensor heater or circuit fault." Please double-check this number. My book says DTC 0101 is caused by the Camshaft Position Sensor (Phase). This sensor is located on the engine front cover facing the camshaft sprocket. It detects the cylinder number signal. The Engine Control Module uses this signal to control spark plug firing order and also to sequence the fuel injectors correctly. If the CPS is bad the ECM will fire the plugs at the wrong time, or not fire them at all. This would account for a no-fire symptom.
this is from the stickies
and the thread it came from
http://forums.maxima.org/showthread....highlight=0701
and just in case you werent paying attention, P0300 is 0701
Thread Starter
Junior Member
Joined: Mar 2007
Posts: 35
Not very throughly. It has been a few weeks but I replaced 3 and 5 when I replaced my plugs. The rest were alright but still get a light and some missing >.>
I looked at the stickies but I guess not hard enough.
I looked at the stickies but I guess not hard enough.
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Kyle Lee Cleveland
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Sep 28, 2015 09:01 PM