Hello,
My scanner is showing that my oxygen sensor output voltage for b1-s2 and b2-s2 is always 0.
What should I check next?
Thanks for your time.
Jomo

 

Fuse # 14 / 10 amp right engine bay fuse box for the sensors to be heated up ( heating element inside which is an easy check for that ) for them to operate properly

The input is 5 volts and the output is around 3.5 off the top of my head

The O2 sensors on the X300 are Titania based and not the more common

The scanner may not be able to read them and is looking for the more common type

To know that your O2 sensors are regulating the engine as the final competed outcome the Short Term Fuel Trim should be close to target value 0 % in all RPM / Load regimes

The dynamic moving graph is hard to discern but goes like this

If the sensors see an access amount of unconsumed O2 the computer will enrichen the mixture

More common you will have too little O2 as the mixture is too rich ( negative STFT number )

The range limit of the reader is + or - 25.4 % so that value is seen often as the regulation is not honed in to effecient

 

Hi Jomo,

Please tell us the rest of the story. What are the symptoms that prompted you to check O2S signals? Is the Check Engine Light illuminated? Are any Diagnostic Trouble Codes stored?

The X300 On-Board Diagnostics system is very early and primitive, and in my experience it cannot always be relied upon to give correct data.

Cheers,

Don

 

Good question. I put the information in my previous post from yesterday, but of course you would not know that. Here are the engine codes that come up: I have the following 5 codes on my 95 xj6: p1193, p1185-86, p015 B2, S2 and p013 B1, S2.

 

Symptoms ?

Codes are one thing and mechanicing is another sometimes not well connected

 

The car drives very well.

 

Hiway milage ? there is a button to press on the instrument cluster to see real time gas milage

Acceleration lacking ?

Idle RPMs ?

 

22 mpg on hi way
Accelerates fine.
Idle RPM is between 695-705

 

I am attaching the DTC Summaries manual, which gives the published definitions and possible causes of each DTC. P015 and P013 are incomplete - there should be four numerical digits in the code. Here are the definitions of the other codes:






Have you done any work on the car during which the O2S electrical connectors might have been switched?

Is it possible that a rodent has chewed the O2S wires?

It is uncommon for two oxygen sensors to fail simultaneously...

P.S. In what thread did you make your previous post? I can move it here so all the pertinent information is together.

Cheers,

Don

 

You're probably driving in open loop, so the fueling is not being adjusted by the sensors.

 

Your a little bit low for a 4 .0 liter for highway speed , Question on the instrument cluster computed accuacy

Open / Closed ( efficient ) loop trigger is 88 C of the engine coolant temp senor

Cheap part but can be calibrated against page 78 as your meter will power the thermistor to function to give you a reading

At cool coolant at 86 F / 30 C you should see 1700 ohms

A higher resistance reading would be bad as a colder coolant temp reading ( thermistor reads opposite an old school thermocouple )

jagrepair.com/images/Training Guides/801S - 2000.pdf

 

The on-board computer estimates fuel economy, both the long-term average and "current."

Before and after installing Andy Stoddart's (XJRengineer) 5-degree timing advance bracket on my '93 XJ40, I conducted significant "scientific" fuel economy tests by repeated drives around a 60.0-mile circuit with only 5 stop signs. I would fill up the tank at Shell just prior to embarkation, then fill up at the same pump immediately upon return from the 60.0 mile circuit. I found that the on-board computer was consistently between 1.5 and 2 mpg off from actual fuel use, but it could be either high or low.

P.S. With Andy's bracket, actual fuel economy improved by almost 2 mpg, and mid- to upper-rpm performance improved also. I highly recommend his bracket to owners of late AJ6 and all AJ16 engines.

Cheers,

Don

 

The computer makes assumptions that may not be true in service

Like an ELM - 327 reader that gives Horsepower ............ really

 

Is there a reason why we are assuming the O2 sensors are ok?
I know that components don’t often go bad in pairs, but as we know, you can happily drive without knowing a sensor is dead.

 

Hi,
I pulled out the easy two O2 sensors and will be checking them later. I assure you that I know just how to reconnect them--that is, I will not wire them backwards. My question is where are the connectors for those rear O2 sensors? A picture and some instructions will be helpful!.
Thanks for your time!
Jomo

 

Can someone please let me know how to get to the downstream plugs for the o2 sensors on my 95 xj6? I'd love to get this cat back on the road!