my 05 XJR just went into Restricted Performance mode and threw P2601,, no CEL,,
i pulled over and restarted the engine and RP was gone,,

please,, help,,

 

my indy checked the SC water pump and found it operating,,
any other possible reason to have the P2601?

 

anyone installed a johnson cm30 i/c pump on X350 R?

 

anyone?

 

P2601 is listed as being for the Auxiliary Coolant Pump. Isn't that the one for the Climate Control, not the S/C?

 

i don't see why it goes into RP due to heater pump,, heater would simply not work,, so i believe its the SC coolant pump,, i also experience engine rattle and pinging in acceleration,,
car also throws P1646,, and yet no CEL,,

 

I thought it odd that a problem with the Auxiliary pump would cause RP as well but, unless there is an error in the workshop manual, there is a different code for a S/C coolant pump malfunction. Maybe it is a red-herring?

 

i/c coolant pump code found in manual P1474 and said to kick amber light,,
now am consused,,

 

i checked the i/c coolant pump and found it not working,, i have an extra DENSO MNA6710AB which is the heater auxiliary pump,, would this pump fit and compensate?

 

Hi there
I got the same 2601 SC coolant error and my engine has pinging going on as well. How did you go rectifying these problems. Also any news about the Johnson CM30 SC pump
regards
Joe

 

Wow - thread resurrection!!

Change the SC pump / check all its wiring.

Search if you want more info but it may take real effort as this issue is rare.

 

Changed the sc coolant pump with a second hand one and the RP error still present but not all the time.
Any ideas?? Please??

 

Just about could be the IAT2 but do you definitely have coolant flow? Changed pump does not guarantee that...