Check Engine Light

To do this you will need a code reader. You can find them at most auto parts stores. Once it interfaces with the vehicle's computer, you can instruct it to clear the warnings.

The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are a common cause of multi-cylinder misfiring. If no leaks are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem.

Possible causes,
Faulty spark plugs
Faulty ignition coils
Clogged or faulty fuel injectors
Intake air leak
Fuel injectors harness is open or shorted
Fuel Injectors circuit poor electrical connection
Ignition coils harness is open or shorted
Ignition coils circuit poor electrical connection
Insufficient cylinders compression
Incorrect fuel pressure

'Well I have a 95 Buick LeSabre, and the check engine light keeps coming on. So I asked a guy at car-x, and he said that usually occurs when you go really slow on the interstate.'

That would be a good problem to repair even if it's NOT causing the check engine light to come on... but I would suspect yes, depending on the manufacturer.

go to autozone and see why its on, they check it free. One word of caution however, they will give you the code, they do not diagnose the problem. They may guess and suggest a part(as they sell parts)based on the code description, but this is still a shot in the dark.

I had a light on and I went to Advance Autoparts and the counter guy printed out a history of codes, all of which came back that my O2 sensor on the tailpipe was faulty. When I changed the sensor, I had to diconnect the battery to reset the warning light. You have to leave it disconnected about 1/2 hour to reset.

Before going to Autozone and checking codes, try the "reset" button located in the fuse box (open driver's door and look on the side of the dash). Key in the "on" position, engine not running, hold the reset button until you hear the chime ring a couple of times. Once the light is reset, if it comes back on within several miles of driving I would definitely have it checked out.

There can be several reasons for the light to come on. It can be because the O2 sensor has been eliminated with the U-bend delete or it can sometimes be related to the CAI modification. The high flow cat can also set off the SES light as the rear O2 sensor (if applicable) will "think" that the cat is not performing correctly. Get your engine scanned to know for sure. Many popular auto parts retailers will do it for free. For related info on your modified engine see the postings on www.clubgp.com Hope this helps.

disconnect the battery cable and wait a few minutes. You must have your code for the radio to work once you hook the battery back up.

If the check engine light is flashing that means an engine cylinder misfire has been detected

po320 is the engine speed circuit malfunctioning.( AKA) crank sensor.

That generally means a misfire has been detected. See related questions below.

You have it checked for codes and diagnose the cause of the code.

I have a Jaguar XJS 1993 model. A light on the dash has come on saying 'check engine'. Using the hadbook procedure the faull FF44 has appeared. I believe the FF stands for Fueling Fault but I do not know what the 44 means

If it is the MIL code you are talking about, my manual shows 31 as being associated with the EVAP system. Problem is that there are many "31" codes for EVAP. What is needed is the scan code. Like P1495 or P1494.

All of these scan codes are listed under a "31" MIL code.

P0443: EVAP emission control system purge valve C fault.

P0441: Insufficient or excessive vapor flow detected.

P0442: EVAP emission control system leak (small)

P0445: Leak detection monitor is unable to pressurize the system (large leak)

P1486: Plug or pinch detected between purge solenoid and fuel tank.

P1495: Leak detection pump solenoid circuit fault.

P1494: Leak detection pump switch does not respond to input.

You can get more info on the scan codes at you local library. Locally here (Seattle), I can access All Data and Chilton via the library. No fee. I assume you have the same.

Good luck.

you do not fix the light. you fix what ever caused the light to come on. so the lenght of time depends on the cause for the light to go on on the first place.

hey dude call up advance auto parts and give them the code and they will look the code number up in the book. i know it because i work there and use the book everyday. goodluck Answer

I own an 89 Dodge Dakota and from my experiences and research the reason that the check engine light does not stay on is because it goes into what is called a "limp in mode" which helps get you to a service station. If you have a Haynes manual or can get one, foudn at NAPA and Advacned Auto, you can look up the code fairly easy. I know that on mine the check engine light has never stayed on but the computer stores the code until it is cleared. I hope I have been helpful.

1999 Pathfinder: I had the computer checked 3 times. But no code was identified that pointed to any specific problem. Each reset caused the light to go away for different periods of time. Anywhere from 2 weeks to 4 weeks. Once it even went on and off within several days on its own. Best guess was emmissions, fuel, or loose connection on something. The car runs fine with no other symptoms. The light has been on now for 2 weeks. I'll reset again, have my mecahnic look over the engine, and see what happens. My 2000 Pathfinder has run with the check engine light on since 20,000 miles I now have 149,000 miles. It started when I changed the air filter to a K&N. My local mechanic has checked it numerous times and the computer shows no problems. You may want to check the air filter. I also own a 2002 Pathfinder the check engine light came on due to the seal on the fuel cap not making a proper seal. I replaced the seal and the light reset and has not come back on in a year.

disconnect the battery

It could be fuel pump, fuel filter or out of fuel. To be certain, you can always use a code scanner to see if there are any stored codes.

Check the codes with an OBD2 scan tool.

engine emissions not good .. get obd2 scan most probley your cat converter

Most likely one or more of your cylinders is not firing properly. Take it to a mechanic; they've got a device that plugs into your car and reads the diagnostic code telling you why the engine check light is on, which will be more informative than us attempting to guess.

key on,left turn signal on, press lower left and upper right speed control buttons

bad o2 sensor on left bank