Sensor Questions for S13

[Thoughtful_One]

Can the CTS malfunction, but not throw a code?

Also, last year I had replaced the O2 senor in my car. I failed emissions yesterday in my inspection and when my mechanic checked it out, it turned out that the car gave a code for that sensor. After he replaced the sensor with a new Bosch one (the old one was Bosch), it passed with flying colors. Why would the old Bosch one fail? I also noticed that low end power has decreased much more than before. What could cause this and what should I do?

[vancouverbc]

that's a short life of an O2 sensor but they do go quite regularly. i think the cts can go and not throw a code. i

this is for 1991 240sx. also applies to maxima, nx, pathfinder, pickup, sentra, stanza, 300zx. for 1991)I think it is the red plug right at the front of engine. easily accessable.

1. Turn ignition switch to "ON" . Engine is off.2. Check voltage between terminal "a" and ground. should be around 5 volts.3. if not 5 volts, repair harness.4.if 5 volts, check ground by turning ignition switch "OFF". Check for continuity between "b" and engine ground.5.if no ground, repair harness and connectors.6. if ground is good, check the sensor itself. at 68 F , you should measure 2100-2900 ohms. at 176 F, you should have a resistance of 300-330.measure resistance across sensor terminals. the sensor obviously is immersed in the coolant.

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Modified by vancouverbc at 6:25 PM 6/7/2006

[180fan]

the cts sure can fail and not throw a code. I usually replace my o2 sensors every year.

[ricebike]

Quote »...the cts sure can fail and not throw a code. I usually replace my o2 sensors every year.[/quote]wow, 180, that's kinda excessive to be doing that... my maintenance records stated that i've changed my 02 sensor ~5 years ago (a lil over 50k miles) & it's still putting out good emission #s... I'm using a bosch unit as well...

I'll only change that part when the ecu has stored a trouble code or when i perform the o2 sensor test= mode 1 on the ecu.... (this is for da KA24E SOHC engines)

the green LED would flash on (lean) & off (rich) a couple o times per minute when the operating temp is up & engine goes into closed loop mode...

[180fan]

Dude, in my neck of the woods, gas costs more than a new o2 and tune up parts at the end of the year if I don't keep the cars tuned up. I'm guessing gas prices haven't reamed you ever so hard yet, but as a student...man I pinch my pennies pretty hard.

[Moto Man]

I replaced my O2 sensor for the first time at 12 years/100,000 miles. The throttle response is a little better, but I haven't noticed any improvement in fuel consumption.

[ricebike]

180,

oops, I forgot that u are in CA... yep, i'm feeling the pinch in NJ since i'm starting to use my credit card to pay for gas & try to pay it off in full every month (but lately, that's not happenin').

still a bit excessive on the 02 though... but that test in mode 1 werkz...

if ECU doesn't throw a code, but Mode 1 test is starting to show me a slow o2 sensor, then I'd jump on it & change the sucker out.

+ I keep a gas mileage log as well... so when I see my MPG drop, time to check over my car!