2000 Infiniti I30 Cat Converter? Dead or a Bad O2 Sensor?

catalytic-converters
infiniti
i30

#1

The “Service Engine” light is on and the stored code is P0430. 144,000 miles and the front tube and sensors were replaced in a recall three years ago. Before I surrender to the gentle and expensive ministrations of the Infiniti dealer, here is my question: How likely is it that the O2 sensor and not the converter is bad? A new sensor is about $200 and an aftermarket converter is about $300, but neither one is returnable if I replace it myself and guess wrong. Any insights?


#2

An exhaust leak or a bad O2 sensor will trigger this code.

Look for an exhaust leak and measure the output from the O2 sensor. You’ll need a service manual to give you the specs.

Why would you want to go to the Infinity dealer? Any decent mechanic should be able to diagnose and repair this.


#3

Actually, I wouldn’t go to the dealer. There’s an excellent mechanic nearby. No exhaust leak – checked thoroughly. The electical test requires a dual-input voltmeter, where you count the switching rate of each sensor simultaneously at 2,000 RPM and then calculate the ratio to see if it’s within limits.

I may be whistling past the graveyard here – but I just spent $1,400 having my other car fixed and it would be nice if I could do the repair myself.


#4

Well, if you can quote the specs, you should be able to do it yourself. Do you have a dual-input voltmeter? Do you have an O2 sensor socket?

If not, this is a perfect opportunity to add to your tool collection.


#5

At 144k miles, there is an excellent possibility that the other O2 sensors are getting too slow to satisfy your OBD II control system.

I would not trust the verdict of a voltmeter, even a dual input voltmeter, when it comes to identifying an aging O2 sensor. You really need an oscilloscope to see if it is still up to par.

A new OEM oxygen sensor for this car is $110 on line with free shipping from any of several reputable sources. If you take it to a shop, whatever the problem turns out to be, you are almost certainly going to end up with a new sensor, so you really have nothing to loose trying it yourself.


#6

That’s my thinking as well, especially since the trouble code is intermittent. If I clear the code, sometimes the car will go weeks before it resets, and other times it’s just a few hours. So I’m going to start with the sensor and if that fails, an after-market front cat converter is about $250. Thanks for your advice