I am using a icarsoft i930 scanner. Under the OBDII Diagnose option there is a test for the EVAP System, however the directions warn that “before using, refer to the vehicle’s service repair Manuel to determine the procedure to stop the test.” I Googled up such instructions and found a lot of “google” that was beyond my understanding.

Any suggestions on the “stop the test” procedure?

i envision punching the iCarsoft button and a testing loop begins that last forever!

 

In general, you can force an evap test by having the computer activate the purge valve and all that. I'd say hold off on that for now. I was instead talking about getting the status of the individual OBD monitors (catalytic converters, heated O2 sensors, component, evap, ...). There should also be an option to see pending codes. This should be under that OBDII diagnose section, as this is not JLR specific.

 

Timely thread for me and my 2001 XK8. My CEL has been on for a week. I took off the gas cap (no whoosh) and ran the OBD tests. It came back with 4 Jag-specific codes. I didn't bother to look them up, but used the OBD to clear them. And the CEL is now off, and there are no codes on retest. Maybe it was the gas cap, maybe not.
These cars are very touchy about voltage. I think it's all the digital boxes. I replaced the flooded battery with an AGM and have fewer warning lights. And disconnecting and reconnecting the battery has always cleared them so far. I'll post if there is any change.

 

Running the I\M Readiness appears to tell what is incomplete:
Comprehensive Comp monitor is INC
Oxygen Sensor is INC
Oxygen sensor heater is OK
EGR and/Or VVT is OK
misfire monitor is OK
Fuel System monitor is OK
Catalytic monitor is OK
Heated catalytic monitor NA
Evaporative System monitor OK
Secondary air sys is NA

O2 SENSOR TEST
Bank 1 Sensor 1 - does not support
Bank 1 Sensor 2 $03 Low Sensor voltage - pass, $04 high sensor voltage - Pass, $07 Min Sensor voltage - pass and $08 Max Sensor voltage - Pass
Bank 2 Sensor 1 - does not support
Bank 2 Sensor 2 - does not support

ON BOARD MONITOR
Test $06,$07,$08,$13,$14,$1A, $1B, $1C,$1D,$1E, $F — ALL Pass

Except PASS the rest is Greek to me.

 

My MAP numbers sit at .8 at idle. XK8 Bible says number should be 3.7 lb/min at idle! I cleaned the MAP sensor with proper cleaner and also cleaned electrical connections. Air duct appears new with no leaks.

cranked engine to check numbers and got the same .8 lb/min but it does increase as throttle increases.

got RP light during test while idling!

any thoughts?

 

yes the Restricted Performance and CEL light come only when idling, low speed or accelerating . The knock sensor is a single bank.

thanks
Bill

 

There is Manifold Absolute Pressure (MAP) and Mass Air Flow (MAF). MAP is just pressure, MAF if flow (mass per unit of time). You are looking at 2 different sensors I think.

 

I got my F's and P's mixed up. I cleaned the MAF but despite the cleaning my MAF is still at .7 lb/min. The MAP is 9.9 Hg at idle. But after using Techron treatment it does seem to be running better. However, at idle or slow speed the RP light will come on - no problem with RP at speed.

 

I am running on my second tank of Techron and things seem to be improving but still getting a sporadic RP light but it has not thrown up the knock sensor code lately - one knock sensor code stored but with exception of P1000 code no other codes pending.

this is a screenshot of OBDII reader. Do these number look good or do any of you spot any problems?

thanks,
Bill



This is at idle.

 

On that shot your MAP sensor is not working/being read correctly as it is showing atmospheric pressure

 

Wight8 thanks for the reply however I am confused. According to the XK8 Bible the MAP reading should be 10 inHg. If I am reading it correctly, my screen shot reads 29 inHg. Am I misunderstanding the XK8 Bible?

I am definitely a rookie at the OBD11 coding.

Thanks,

Bill

 

The Manifold Absolute Pressure is just that, it measures the Absolute pressure, in other words without the engine running - or if you took it out, it would read 29.9 inHg - which is the Absolute pressure at sea level, or for us over the pond 1 Bar or 1 atmosphere. With the engine running you have vacuum in the manifold so you have LESS pressure - I have not checked but 10 inhg sounds about right. Your engine thinks you are at full throttle so it will be rich and have the ignition retarded.
Take a look here for an in depth explanation https://www.aa1car.com/library/map_sensors.htm
Looking at the manual, if the MAP sensor is broken it substitutes the 29.9 value but it should also set P105/6/7/8

 

Wight8, thanks I now have a better understanding of both MAP and MAF but no the only codes that pop up are P0328 knock sensor and P1000. After changing the fuel filter, cleaning the MAF sensor, checking for visual cracked hoses - nothing obvious but no smoke test, as well as two two tanks of Techron I decided to let a professional look it over.

I will I’ll let everyone know what he finds out.

Thanks all

Bill

 

It appears the issue was in the knock sensor. After exhausting my own expertise through the suggestions and advice from you folks in the forum, I gave in and carried my XK8 to a Indy shop. They checked it out replaced both knock sensors as well as the heater and vacuum line running under in intake manifold. All seems good. Just came back from a 388 mile jaunt that included a car show - Brits on the Bluff in Natchez MS.

No Restricted Performance nor Check Engine lights, made new Jag friends and to top it off, received a second place ribbon!

Thanks all for the suggestions, help and concern.

 

Thanks for the update !

Though I suspect was what fixed it!