Hi Guys/Tech's

98 Jaguar XJR. Have two Codes P-1638 and P-1642 I have just a general tool and not the Jag fact tool and I am stumped.

I have cleaned EVERY electrical Connection. ZERO vacumme leaks. Cleaned the MAF and reinstalled it.

Car goes into limp mode, gauges/tack/fuel/temp all shut off and feels like the brakes are on. turn car off and on a couple of times and goes away and drive, then reoccurs.

ANY "Help" would be most appreciated!

rlover

 

Nobody has any input on this? I'm looking at a used car that reports these same errors but it seems to behave normally, at least for 30 minutes at a time, the longest I have run it.

EDIT: I see this was reposted elsewhere with replies. NM. The car I'm looking at has (apparently) a bad ABS module which I think can cause these errors.

 

Mike:
Most of the times, I believe this fault is an artifact of connecting the scanner software to the CAN bus. However, in your case, apparently there are symptoms that could very well a result of the bus failure. Or not. Finding an actual CAN bus failure would either require a sophisticated bus sniffer or parts exchange. Good luck.

 

I have the SAME problem! What was the problem?

 

Sorry to hear that. It was the ABS control pump, it is located at the drivers, front of the engine, behind the drivers headlights. I also replaced the ABS control module as well. The circuit loop of the CAN system is terrible for diag the problem. With those codes, it could have been the instrument cluster, ECM as well. Try cleaning off ALL of the speed sensors. Remove the ABS pump, 10 plungers i think in the pump, push down on the all plungers, remove all the brake fluid and see if that helps? If not, Ebay or a salvage yard is the best place to go to buy, the Jag dealer is $2,200 for the Pump and the Control module is almost a grand. My pump was 325 and the ABS module was 275 from a salvage yard.

Good luck,

Rlover

 

Viapa:
Is your problem the codes, or is it that you go into restricted performance and also get 1638 and 1642?

 

Well, the way a can bus is tested in industrial applications is with an oscilloscope. You might try cleaning the can bus connectors on those modules. Is the problem intermittent after 30 minutes or does it hang and stay? If you restart after 30 minutes, does it return immediately or in 30 minutes? It is entirely possible that any module on the bus is failing.

 

Here is a TSB for you!!!!!!!!!!!!!!!!!

bob gauff

 

The fact you have BOTH of those codes, repeatedly, tells us there is something going on there. That means something is in fact taking the CAN network down. The problem is you can't see all the faults that are set when the failure occurs. Particularly with the P1642, there is probably a corresponding fault that shows up in another module, possibly the offending module, that might help point you toward the real problem. It just takes the Jaguar diagnostic tool to be sure you can read everything.

Your mention of "feels like the brakes are on" makes me want to suspect the ABS module, but that could be proven wrong.

Attached is some info you can use to prove out the circuit integrity of the CAN network, and hopefully rule out that.

Good luck!