Hey guys I went to my local Jag workshop to get my A/C recharged. He only had to add few oz to it, but he did notice that my pressure valve on the compressor is going bad b/c the High pressure gauge kept flickering around like crazy, but once you step on the gas a little it levels out. So thats how he knew the pressure valve is getting bad and needs to be changed soon.

Is it possible to buy a separate pressure valve or you have to get a whole new compressor?

While it was charging I had one of the techs hook up his IDS scan tool and check for any codes. He saw that the "M.A.P Sensor" pulled up. But the thing is I didn't get any CEL. He told me if the MAP sensor goes bad it will pull out a CEL on the dash. His conclusion was that it was an old code still logged in the computer, so anyhow he reset it and told me to drive it abit, and check back later to make sure its not pulling the MAP sensor code again.

To clarify will a bad M.A.P sensor pull up a CEL? and is it a difficult job to replace?

Thanks to all who reply back.

 

map sensor will trip a cel. I think there is 2 map sensors, one on the intake elbow which is hard to get to and another on the intercooler.

 

It could have such a large build up of oil on it causing a very rare reading out of range but it didn't happen often enough to trip a cel. If you have extra time it wouldn't hurt to pull it out and get some MAFS cleaner to spray it with.

 

Only one MAP. You're meaning the 2 IATs the STR (only) has.

Bad MAP (or any sensor) will only trigger a MIL if it's bad in similarish ways in the right circumstances. A really bad sensor will be, but a marginal sensor or wiring/connector may well not be detectable. The reason is that potholes etc would trigger endless codes so occasional bad values are internally flagged but don't cause a MIL (code).

Codes are kept a long time but eventually are silently deleted if the cause does not recur.

Having cleared it, the associated data has been lost, sadly.

You now should check that all the OBD monitors run OK ("Complete" or "Set"). Almost no codes can be flagged unless they do and also you'd fail state inspections (if they apply to you).

If they don't Complete, be afraid. You'll be hunting a definite problem but very possibly without having any codes!! Yes, occasionally this does happen and is why a careless attitude to code clearing is not wise.

Fortunately the S-Types are quite solid OBD-wise so your chances are good.

 

...after digging around I found some info on the XJ threads
https://www.jaguarforums.com/forum/x...p-sensor-6914/

Cleaning the MAP sensor of carbon build could also be a solution, but anyhow I 'm going to drive it for a few days then take it back to see if the code popped up. Would any good OBD 2 scanner pull out a MAP sensor code? or do I have to go back to the workshop who uses the IDS scanning tool which seems to be more in depth?

That was the only code that was pulling up on the scan tool, nothing related to the 02 sensors which is odd, you would figure if the Map sensor isn't working right you would get an 02 sensor problem and that would trigger a CEL as well. But neither happened to me.

 

I don't see why you say that about the O2s. It's not logical.

Any OBD tool at all should be fine. I'd use an elm327