CO2 Sensors

[OLDSPUD]

On my '03 chev 2500 (gas), my engine light has been coming on then going off the last few times I have been driving it. Somrtimes it will come on then go off even on the same short drive.

I decided to have the computer checked and it read out that 2 of the 4 co2 sensors are either going out or not operting properly.

The truck needs to be registered this coming June, so I have decided to just worry about it then.

Can anyone see any reason the deal with this now? The truck has about 70K miles and rus as though it is brand new. I have kept it with highest regard, the truck even looks new. i plan on selling it as soon as Chev comes out with the 2500 flex fuel or whatever they call the four to eight cylinder system they have on the 1500's.

thanks

Spud

 

[dolluper]

Re: CO2 Sensors

Which engine do you have? key here is you say short drive as the two closest to the cat are heated O2 sensors.....are they the ones failing? if so warm here up before you drive and try a tank of high priced....high octane once in a while to clean them better

 

[OLDSPUD]

Re: CO2 Sensors

It is a 6.0 ltr engine, and I am one of the most particular people when it comes to what type gas and/or oil products that enter that truck. 75% of the time I pruchase plus grade Chevron fuel, the other times I will upgrade to supreme.

I use only Mobile One syn oil, and change of a very good schedule.

I also thought that the results may be due to reduced use of the truck, and not runing enough. It has sat in my shop for the last year with very little use. The only use I give it is to pull my boat.

Last week I did take it on a six hour run at freeway speeds, not much changed as far as the sensors go.

Spud

 

[Bob_VT]

Re: CO2 Sensors

Have someone with a scan tool turn off the light and see how long it takes to come back on...... ie... long enough for an inspection

I would also run a can of sea foam through the truck or chevron (with techron) through it and hope it helps clean it off a bit.

Push comes to shove you are going to end up putting sensors in. If you have a check engine light the ecu goes into "default" mode and can mess up your MPG.

 

[bruceb58]

Re: CO2 Sensors

No fuel cleaner is going to do anything to help your O2 sensors. 70K miles is not an unusual time to have to replace these. I would just bite the bullet and replace them now. Clearing the codes also resets a counter that indicates how many cold starts have occurred since the last clear. Some states require a certain number of starts to have occurred since the last clear so clearing the codes right before a smog test will cause you vehicle to fail the smog test.

Codes will be set for various reasons on the sensors. One of them is if it detects the heater circuit not working. If it is just the heater, you can run your truck for awhile without it effecting the performance. If the sensor is not putting out the proper voltage range, it is possible that the ECM will put the vehicle in a default open-loop mode which could cause your fuel economy to drop as it will put in an over-rich mode. You may end up burning more extra fuel that what is costs to replace the sensors.

 

[JCF350]

Re: CO2 Sensors

Change them and be done with it. No sense wasting time with other stuff.

 

[MrBigStuff]

Re: CO2 Sensors

Clearing the codes also resets a counter that indicates how many cold starts have occurred since the last clear. Some states require a certain number of starts to have occurred since the last clear so clearing the codes right before a smog test will cause you vehicle to fail the smog test.

Just to clarify, OBDII includes a number of system "monitors". These firmware routines are responsible for monitoring the state of sensors and sub-systems related to emissions control/monitoring.

Each monitor has its own set of conditions that must be met before it becomes "ready". When you disconnect the battery or clear the codes using a scan tool, the monitors are also reset. What they take to become ready again, varies by the type of monitor and the vehicle manufacturer. EVAP monitors are different than the O2 monitors for example. The EVAP monitor may be related only to # of starts without a fault whereas the O2 monitor requires a variety of operating conditions be met before it will become ready.

The emissions testers hook up an OBDII scanner and if there are any stored, active codes or any of the monitors are not ready, you will fail the test.

 

[thefairlaneman]

Re: CO2 Sensors

On my '03 chev 2500 (gas), my engine light has been coming on then going off the last few times I have been driving it. Somrtimes it will come on then go off even on the same short drive.

I decided to have the computer checked and it read out that 2 of the 4 co2 sensors are either going out or not operting properly.

The truck needs to be registered this coming June, so I have decided to just worry about it then.

Can anyone see any reason the deal with this now? The truck has about 70K miles and rus as though it is brand new. I have kept it with highest regard, the truck even looks new. i plan on selling it as soon as Chev comes out with the 2500 flex fuel or whatever they call the four to eight cylinder system they have on the 1500's.

thanks

Spud

The last time GM tried making an engine to switch from 8 to 4 it was 100% junk,Have they learned how to do it right this time?

 

[fishmen111]

Re: CO2 Sensors

Change them. If it is just the heaters taking too long then you will just throw codes. If it is the sensor voltage itself, then you are wasting gas and risking going into failsafe mode where the engine will richen the A/F ratio to a preset to protect the motor. 70k miles is about average of when most manufacturers suggest inspecting and/or changing them. Not to be anal, but they are oxygen (O2) sensors not carbon dioxide (Co2).

 

[bruceb58]

Re: CO2 Sensors

Not to be anal, but they are oxygen (O2) sensors not carbon dioxide (Co2).

Everyone except the original poster has been calling them O2 sensors.

 

[fishmen111]

Re: CO2 Sensors

Sorry Bruce...that's who I intended it for.

 

[TilliamWe]

Re: CO2 Sensors

OldSpud, "FlexFuel" is not the same thing as "Cylinder Deactivation." FlexFuel means it can run on E85.
Fairlane, you would "hope" that GM got it right this time. I have to believe they did, cause Chrysler is using their "MDS technology" to do the same thing.

 

[OLDSPUD]

Re: CO2 Sensors

Thanks guys, I will have them replaced. You answered my question. I will make the appointment.
Ya, cylinder deactivation is what I am talking about, I am supposing that in pull boat mode, this will never come into play, 'cept mayby going down a long hill. I like driving my truck, and it would be nice to get double the gas milage on a general ride.

 

[JustJason]

Re: CO2 Sensors

before you replace them double check the return voltage on both sides of the actual 02 connector.

 

[JCF350]

Re: CO2 Sensors

The values are shown in the scan tool data stream displays.
His O2 sensors don't really have a "return voltage" as they generate their own.

Code readers do get a lot of parts replaced unnecessarily, and your point is still valid if that's all that used however.

 

[thefairlaneman]

Re: CO2 Sensors

OldSpud, "FlexFuel" is not the same thing as "Cylinder Deactivation." FlexFuel means it can run on E85.
Fairlane, you would "hope" that GM got it right this time. I have to believe they did, cause Chrysler is using their "MDS technology" to do the same thing.

OHHHHHH! I guess Im too much "old school

 

[puddle jumper]

Re: CO2 Sensors

Just food for thought a plugged fuel filter, vacuum leek or an exhaust leak forward of the o2s can also cause an o2 sensor to read lean and cause an check engine light with o2 codes. I would get it scanned and if all o2s fail look for other problems first before just replacing them.

 

[JCF350]

Re: CO2 Sensors

Yep
http://autorepair.about.com/cs/troubleshooting/l/bl_obd_1.htm

Note the quantity of different O2 codes and conditions that the O2 will set.

These are the generic codes BTW the codes that start P1xxx are the manufacturer specific ones which include a few more.