Tilted Forum Project Discussion Community - View Single Post - Anyone ever has mechanical car questions, ask me in here :)

Sion · 11-15-2003, 07:58 AM

th O2 light? Isuzu's have a light specifically for the O2 sensor? or is it the MUCH more common Check Engine/Service Engine Soon light?

if the latter, there are LOTS of reasons why it could be coming on, one of them being the O2 sensor circuit. But, as you were told, disconnecting the battery for a minute or two will wipe any codes stored in the computer's memory. Another way to do this would be to remove the fuse that protects the circuit that supplies power to the computer.

If the light still comes on after a battery disconnect, then you will need to pull the trouble code that is logged in the computer. This can often be done fairly quickly at a parts store (usually for free) or by most shops that do engine/tuneup work (usually for about $20 or so). Once you have the code, you will need to determine what it means.

For example, if a trouble code indicates that there is a problem with the O2 circuit, that does NOT necessarily mean that the O2 sensor is bad, just that the response the computer is getting from that circuit is either out of the expected range or even non-existant. The circuit in question needs to be checked. Even if there is no problem with all the wiring in the circuit, there can be other problems besides just the sensor that can throw this code. For example, if one of the cylinders is not firing correctly (say a bad spark plug or wire) then the unburnt gas/air charge is going directly into the exhaust (where the O2 sensor is located) and can throw an O2 code, even though the circuit itself is good.

So, in other words, dont just throw a sensor at the problem and assume it will solve it. Proper diagnostic procedures must be followed to be sure that you are treating the source of the problem and not just the symptom.

good luck

11-15-2003, 07:58 AM	#7 (permalink)
Sion Dumb all over...a little ugly on the side Location: In the room where the giant fire puffer works, and the torture never stops.	th O2 light? Isuzu's have a light specifically for the O2 sensor? or is it the MUCH more common Check Engine/Service Engine Soon light? if the latter, there are LOTS of reasons why it could be coming on, one of them being the O2 sensor circuit. But, as you were told, disconnecting the battery for a minute or two will wipe any codes stored in the computer's memory. Another way to do this would be to remove the fuse that protects the circuit that supplies power to the computer. If the light still comes on after a battery disconnect, then you will need to pull the trouble code that is logged in the computer. This can often be done fairly quickly at a parts store (usually for free) or by most shops that do engine/tuneup work (usually for about $20 or so). Once you have the code, you will need to determine what it means. For example, if a trouble code indicates that there is a problem with the O2 circuit, that does NOT necessarily mean that the O2 sensor is bad, just that the response the computer is getting from that circuit is either out of the expected range or even non-existant. The circuit in question needs to be checked. Even if there is no problem with all the wiring in the circuit, there can be other problems besides just the sensor that can throw this code. For example, if one of the cylinders is not firing correctly (say a bad spark plug or wire) then the unburnt gas/air charge is going directly into the exhaust (where the O2 sensor is located) and can throw an O2 code, even though the circuit itself is good. So, in other words, dont just throw a sensor at the problem and assume it will solve it. Proper diagnostic procedures must be followed to be sure that you are treating the source of the problem and not just the symptom. good luck __________________ He's the best, of course, of all the worst. Some wrong been done, he done it first. -fz I jus' want ta thank you...falettinme...be mice elf...agin...