Justaguy

I keep getting this 0503 code (problem with front Oxygen right side...) The OS was replaced, wires were checked and I still get this code.
The car does seem to mis-fire, and I feel the loss of power when driving (I guess cylinder 1-3-5 is misfiring)?

The spark plugs were also replaced with the recommend NGK.

Fuel Filter was not changed
Injectors was not cleaned

Cleaned Throttle body
Changed Air Filter
Changed Knock Sensor
Replaced PCV Valve

Is my next option replacing 1, 3 or 5 ignition coil??

Thanks

1997 maxima, 90,000 miles

Justaguy

..I also noticed this little strange, maybe hidden feature..

When I reset the ECU, I turned the screw to quicky twice, and the ECU was not properly reset. I started the car and drove off..I notice that the "Check engine light" was blinking..hummm..if I let go the gas, it stopped, when I added gas it blinked faster, and at about 40mph, it just stayed on (did not blink)...when I slowed down it would blink at various speeds until it would stop blinking when fully stopped...I wonder if this is some kind of "debug" mode for the 0503 code to pinpoint which cylinder is misfiring

just a thought..

njmodi

iTrader: (4)

Which O2 sensor did you replace? i.e which one do you think is the front-ride side?
(I just want to make sure you replaced the right sensor).

A flashing CEL indicates a severe misfire... not good.

Loe max

iTrader: (6)

You didn't reset the ECU, you placed the ECU into a 'real' time diagnosis mode.

Justaguy

It was the very first one...the 1st pipe going down to the motor.

njmodi

iTrader: (4)

Don't know what you mean by first pipe, there are ar 2 in there - here is a pic:
http://www.courtesyparts.com/A32_O2-sensors.html

You should have replaced the one marked Front Passenger Side (RH) - in the y-pipe, closest to the firewall.

Justaguy

dam. I replaced the wrong one then. When you open the hood and look down, that is the OS I replaced (near the fan) and not the one near the firewall...crap I even thru it out too.

Thanks for the reply and pointing me in the right direction.

njmodi

iTrader: (4)

Oops! well - live and learn - go buy another one and swap out the correct on this time.

Justaguy

..but would this be the cause of my problem?

I hope I don't have multiple problems happening here....reading all these ignition coil problems is getting me all nervous.

If I can ask one more question...has anyone changed the back ignition switch?

thanks

mendon99

iTrader: (15)

if you have an autozone in your area, they can check ignition coils in our cars to see if they're bad. i wish i had known this before i did a bunch of other crap, i had cylinder 2 misfire.. turned out to be the ignition coil.

njmodi

iTrader: (4)

0503 has nothing to do with ignition coils. Replace the O2 sensor.

kelster23

When you replace a bad part do you need to reset the ECU? I've swapped out my O2 sensors and the check engine light has gone off on itself.

njmodi

iTrader: (4)

Yes, you should reset the ECU. However, the light will go off by itself (eventually) once the parts have been replaced, because the ECU will detect that the part is now working properly, and after a preset number of cycles, it will clear the error code.

sflover0099

I just change my Front Right O2 today and I haven't reset the ECU. How long the light will go off by itself? So far, I drove around a bit and the light still on. How to reset the ECU?
Thanks
My car is 1996 GXE