understanding OBD data
#21
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The two diagnostic codes you posted don't necessarily indicate a problem with the MAFS or IATS, but with the electrical circuit for those sensors. It would be worth double-checking the electrical connectors at the MAFS/IATS and at the ECM, since corrosion on those connectors is a known issue.
At the links below you can download the DTC Summaries guide closest to your model year so you can look up the specific Jaguar definitions and possible causes of DTCs:
Jaguar DTC Summaries Guide AJ26 1997
Jaguar DTC Summaries Guide AJ26 1998
Jaguar DTC Summaries Guide AJ27 2000
Jaguar DTC Summaries Guide AJ27 2001 On
If you'll tell us the model year and region of your car (U.K., USA/Canada, France, Germany, etc.), it will help us give you more specific information.
Cheers,
Don
#22
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Thanks Don
Now the ECU is in the box below the tools is that right? Mine appears to be closed with clutch-head screws and one is very tight. What is one supposed to do with those??
MY is 2000 - UK - not sure if AJ26 or 27 see earlier - nicasil I think but no problems on that front - rebuilt 18 months ago with latest steel-backed tensioners & uprated oil pump
Now the ECU is in the box below the tools is that right? Mine appears to be closed with clutch-head screws and one is very tight. What is one supposed to do with those??
MY is 2000 - UK - not sure if AJ26 or 27 see earlier - nicasil I think but no problems on that front - rebuilt 18 months ago with latest steel-backed tensioners & uprated oil pump
Last edited by jayartibee; 10-24-2017 at 08:36 AM.
#23
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A dis-functioning MAF sensor does not give a code, unless disconnected, you will only get a sense if you get other, out of wack data.
Jaguar provided OBD2 data for a well functioning MAF sensor, to be measured in PARK and DRIVE, at idle and higher RPM's.
Looks an AJ26 to me, in that case you will also have a black vacuum reservoir next to the Throttle Body sticking up.
Jaguar provided OBD2 data for a well functioning MAF sensor, to be measured in PARK and DRIVE, at idle and higher RPM's.
Looks an AJ26 to me, in that case you will also have a black vacuum reservoir next to the Throttle Body sticking up.
#24
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![](https://cimg9.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/710x542/capture_9b4e7d7ce9e316b4fc96333450f64b15d76ad5da.png)
Here's the parts diagram from jaguarclassicparts.com; the ECM is part 1:
![](https://cimg0.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/400x569/sm6531_aece23f4c8f7047535a137a795f3e7f5b56e1022.png)
Here's a photo grabbed from eBay:
![](https://cimg3.ibsrv.net/gimg/www.jaguarforums.com-vbulletin/800x600/s_l1600_d67a995363265831e57b87bf2ac2c5ff7fffb509.jpg)
Cheers,
Don
Last edited by Don B; 10-24-2017 at 10:32 PM.
#26