Premium Gas/Knock & O2 Sensors

I bought a used 1996 Nissan Maxima last year. I have been using 87 octane gasoline all year. The knock sensor and O2 sensors have now gone off and I cannot pass inspection until they do not throw codes or I replace the sensors.

Could the use of lower grade gasoline have caused these sensors to throw error codes and if so, can it be reversed by using premium gasoline for awhile (and resetting the check engine light)?


I really doubt if it is the gas, UNLESS, you have been using a gas with a lower octane than Nissan recommends.

How about telling us what error codes you have?

You do NOT change a sensor just because the “check engine” light comes on and a code is set. You do NOT change a sensor just because the “check engine” light comes on and a code is set. You learn what the MESSAGE (code) is from the sensor and do some troubleshooting.

Bring the trouble codes here for suggestions on how and where to begin troubleshooting, AND, what to do BEFORE troubleshooting. You have to get your car in shape (tune) BEFORE troubleshooting begins.

I have read the codes by using the self-diagnose mode (ie flashing codes on check engine light).

I get:
05 03 = Front Right Heated O2 Sensor &
03 04= Knock Sensor

What to do?

Disconnect the battery for 30 seconds, re-connect and drive on…

I can turn off the check engine light without doing that. I have to pass inspection and if I just disable the light it will still show codes or not ready.


your going to have to turn off the light one way or the other. if not you will need at least 3 good trips just to store the codes. Use the battery trick and take a nice long drive on the highway, this should take care of most of your monitors. I know here in GA you only need four of the five in order to get a sticker. if the code comes back you have definite problem. o2 heater codes can be tricky, but usually end up in a sensor.

Does this car have a distributor? If so has anyone checked the timing and if the electronic spark control seems to be working correctly?

the knock sensor failure is a common problem with your engine. The only fix is to replace it.

I don’t understand the codes in that format. I expect to see: “DTC P0123” format.
The sensors MAY be defective, or, not. You can check the oxygen sensor heater circuit. The 12 volt power starts at fuse #15, takes a red/black wire to the front right oxygen sensor, and, on a blue/yellow wire goes to the engine computer terminal #119. You could check for voltage at each end of the circuit (at the #15 fuse, and at the #119 terminal). There should be battery voltage at each point.

Well, here is an update. Before posting this and trying this experiment, I had reset to check engine light 3 times and each time it came back on within a few dozen miles.

Finally, I ran the tank down to 1/4, then filled up with premium gas (recommended for top performance but not required) and reset the check engine light. It never came back on. I am over 300 miles now and still no light.

If there’s a fault in the EGR system (which can occur without setting any EGR codes and often involves clogged passageways) it’s possible that could be behind the problem.
In other words, using Premium is masking over the original problem.

The EGR system is designed for 2 basic purposes. One is to lower NOX emissions and the other is to lower combustion chamber temperatures, with the latter helping to prevent spark knock and hopefully misdiagnosed knock sensors.