Wife's XK8 did it's thing; Electrial Fault, ABs light,
Restricted performance, No ACS............

DTC codes were; P1637, P1642

So have done the following:
Replaced 8 1/2 yo battery (was still good!)
Remove clean & check all 4 wheel sensors (1050ohms)
Checked each wheel sensor circuit at ABS main connector
(again 1050)
Removed ABS control unit and sent to Module Pro
Repair.They said would not fix a P1637!but they resoldered
any way
No difference still P1637.
Checked all grounds.
Sprayed ABS & ECU connectors with CRC cleaner.
No effect....
Did hard reset.....cleared all messages and codes
ran fine UNTIL plug in code reader and every thing returns
Deleted codes with reader; runs fine so plugged in
different code reader.
Lots of messages:
Elecrical fault, Transmission fault,ACS N/A,,
Fail safe engine mode, no tach, Shifter stuck, and no codes!

So used original code reader and deleted all codes.
Back to normal runs fine!

Ind. dealer says will run tests and fix it with their 20
grand computer system BUT may take 10-20 hrs because he
thinks a CAN system continuity problem! Very difficult to
pin point (he says!)
Why does plugging code readers in cause such prolems; same
problems I started with!!

Ideas please, I'm stumped and tired! Wife loves car she's
had it 9 years and wants to keep it!.

Cheers, Adrian

 

Right after a battery problem is ground/B+ corrosion issues. Before spending thousands at a shop I would go through all the electrical connections starting with the battery and working to the ECM including removing and reinstalling the ECM itself. All with cables off the battery.

 

Did all of that..............may replace ECU! Any recommendations for best US supplier other than OEM?

Adrian

 

A rebuild service in TN keeps popping up but headed out the door without time to look it up.

 

Correction, have not looked at ALL connectors between battery and ECM. Did remove ECM and examined circuit board; no signs of leaking components or damage.
Still running fine as long as I don't connect either code readers!
Found a used ECM identical year & part no's except XJ8; will it require a software update?
Will drive 40 miles tomorrow................stay tuned in.

Adrian

 

The XJ8 will require refresh with dealer level software, if it works at all. You can send your ECU to ASI for testing. If it requires repair the test cost is applied.

Automotive Scientific Inc. | Quality Rebuilt Automotive Electronics | Rogersville, TN

 

Slow down.....

Before you send off the ECU for a repair that might not be needed...check this TSB. It looks like you are in the prime effectivity range: http://jagrepair.com/images/TSB/XK8/...%20failure.pdf

The instrument cluster is the hub of all CAN communications.