Ok, I purchased an XK8 with an overheated engine (dropped valve seats) and slipping trans. I rebuilt an AJ26 with AJ27 longblock parts and replaced the transmission and am now working out the codes....

I have a constant ABS/Trac light and a P1649. Could they be related?

Looking for any ideas here, as I have not run across P1649 before....

 

Found this from my 2000 XK8 codes
Code Descriptuon
P1649 ECM flash programming circuit malfunction
Possible cause ECM to DLC circuit, short circuit to ground or short circuit to B+ voltage

 

Any ideas where a good place to start looking for a ground short to ecm would be? I can find my way around a multi meter so I just need to know where the usual spots are.

 

Head to the Electrical Guide in JTIS.

In Section 19 - Ancillaries under Network Serial data Links, look for the SCP (Standard Corporate Protocol) Network schematic detailing the ECM (Engine Control Module) to DLC (Diagnostic Link Connector) circuit.

There looks to be four possible culprits, two of which are common with the Adaptive Damping Control Module.

Graham

 

It is possible the P1649 is spurious
= Flash Communication Control Port malfunction
From what I can make out (and it is damnably obscure) there is a pin on the ECM that is either grounded or set to +12 to enable a reflash.
I'd concentrate on your ABS problem and see if it goes away.

 

Ok- I fixed the solder points on the ABS module (wow, that was EASY- maybe a half hour total.)

The ABS warning seems to have gone away, and I do not have a p1649....I'll cross my fingers. If I do not reply that it is NOT fixed, consider it fixed.

 

UPDATE:
1649 has returned-

When I plug the code reader while the car is running I immediately get an asc code and if I continue to drive with it plugged in the 1649 returns- ideas?

 

Since you say that you get an immediate reaction to plugging in the reader "while running" it boils down to trying plugging it in while ignition is off, or trying another reader. One or the other is related. You are "supposed" to plug in while engine is off, then start.

 

Yes, it does sound like CRAP (Code Reader Activity Problem).

 

I wanted to circle back around on this- RESOLVED

Repaired the ABS solder points, put in a new(er) battery and am ONLY plugging in and using the code reader when the car is not running and key in the on position.

I still do not understand why the code reader being plugged in while running would trigger a code when my XJR does not have the same issue...

 

It just happens - several previous threads on this.