MIL ON and NO Codes?

[SardarQ]

97 Maxima with 66k miles.

I just did a major tune-up on the car which included:

1. Knock sensor and harness2. NGK plugs (thanks for your help NICO)3. Synethic engine oil, mobil 1 filter, synethic brake, PS and transmission oil.4. Alternator (bad bearings)

So I cleared the codes I was getting for the knock sensor and I figured the car is code free.... that wasnt the case for too long

I got the check engine light. I connected a OBD 2 generic scanner and it showed the car has NO codes but the MIL indicator on the scanner turned on.. telling me that the MIL is ON. No shi% ... I could figure that one out by looking at the dash. ($100 well spent on the scanner )

SO I pulled the computer on the side and got codes

33 and 35

33 is the front left O2 sensor and

35 is the EGR temp sensor.

Funny the OBD reader didn't pick that up. Are these codes related? Would one cause the other to tigger?

Any thoughts

[s13sr20chris]

not related. luckily both of those codes generally reflect a failed component. there is a good chance you just need to replace the temp sensor and o2 sensor. generice obd2 scanners are very limited in their ability to scan. i have a top of the line snap-on scanner and an otc genisys(also top of the line) available to me at the tire shop and i frequently find codes i cant see on one or even both. if you want to(and have the capability) you can monitor the voltage from both sensors with a decent multimeter.

if you have the following it will be simple:multimeterleads long enough to reach from sensor to inside cart-pins(like used for sewing or dissection) regular needles will also worksomeone to drive while you watch your meter