davedog

Wife's 2008 CTS CEL is on - P2601

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I just ran into this problem with my 2009 CTS. The engine overheated and threw both the overheat code P1258 and Pump code P2601. I shut it down right when it threw the code and went into limp mode. Does anyone know at what temperature these engines start having problems? 268 degrees seems a little high for me to throw the code. I wish I would have seen the gauge a bit earlier than when the code came up.

I have an Aux pump on order and found that my coolant tank is bone dry. I may not need to replace the pump but it's only $35 and easy to get to. In case it helps anyone else, on a 2009 CTS the Aux pump is higher than the 2008. It's at the top of the radiator on the passenger side. I also plan to park the car facing down hill when I fill up the coolant tank to help get some of the air out. Looks like that might help, but I'm not sure.

What baffles me is that I can't see where the coolant would be leaking out. There's nothing on the ground or in the engine compartment. I have almost 70K on the clock, so if it was really slow, I guess I may not be able to see it. I just hope there isn't a head problem where it's leaking into the cylinders.

Dave, if you're still watching this thread, have you noticed any issues since you made this fix? Engine problems? Low coolant?

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Hi!

I know this is an old thread but I am having the same issues as described above. I'd like to try swapping the horn and aux pump relay but just not quite sure which relay is for the aux pump. Is it the one labelled engine pump beside the horn relay?

Thanks!

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I'm assuming that you have the 3.6L V6.  Looking at the FSM schematic, the engine pump relay has power to the contacts through a 10 Amp fuse labeled ENG PUMP in the same underhood fuse block as the relay.  There is a 16 Amp EMIS 2 fuse that provides power to the engine pump coil.  The ENG PUMP relay is turned on by the PWR TRN relay in the same fuse block.  You should check the exposed points on the two fuses to make sure that there is voltage to the relay points and the relay coil.  The ENG PUMP relay is a normally open, single-pole, single-throw "space saver" relay, probably AC/Delco part number 19116059 (listed for the horn relay; I couldn't find a listing for the engine pump relay), available from Rock Auto for $7.10.  These are all over the car and I would keep a box of them in the toolbox if you plan to keep the car for a few more years.

There are five relays in a row on the underhood fuse block on the short edge, the one that ends in a 45 degree angle.  They are, from the 90 degree corner to the 45 degree corner:

  • Horn relay
  • WSW PUMP
  • AC CMPRSR CLUTCH
  • ENG PUMP
  • RT DRL (HID)

It looks like there are five more of these relays elsewhere on the underhood fuse block, four of them in an L-shaped group on the other side of the fuse block from the five in a row.  They are:

  • LO BEAM (W/O HID) LT DRL (HID) [nearest the long edge away from the five in a row)
  • FOG LAMP [next to the LO BEAM/LT DRL relay]
  • SPARE [center of a row of three]
  • IGN 1 [in the row of three, farthest from the LO BEAM/LT DRL relay]

You should be able to use the SPARE relay to check the ENG PUMP relay.

There should be a label that tells you what all the relays and fuses are.  If not, try to get one from the dealer.  Failing that, come back here and i'll upload an illustration from the FSM.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I didn't go out and look on my own car, but I believe that the diagram that identifies all the fuses and relays is a paper sticker on the bottom side of the cover over the fuse/relay block.  If you have the cover and the big paper sticker isn't there, try to get one locally.  Failing that, I'll upload a graphic from the FSM.


CTS-V_Dashboard.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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