2013 XKR, 36K miles, no other known issues. Battery is less than 6 months old, car behaves flawlessly except for..

The wife and I were in the middle of about a 90 minute (each way) road trip from Mesa up to Payson (if anyone cares.)
She was driving (it's her car) and she drives it like God intended. Made it to Payson, took care of our business and headed home.
I am riding shotgun and wife is doing her thing when we get "Reduced Performance" or whatever it is, don't recall exactly, but you know what I mean.
Made it home on power that felt like a poorly tuned Corolla, but made it.
Pull the codes and get P2601, "Coolant pump 'A' control circuit performance/stuck off." according to my Foxwell reader. No other codes.

Dive into the Forums for a couple of hours, and the likely culprit seems to be the intercooler pump. Order the Bosch version, it arrives and looks like it does in everyone's posts.
Pull the old pump from the bottom of the car, bench test it and it runs fine. Curses. (It does show some calcification around where the pump body mates with the motor, so I don't feel too bad about replacing it.)
The connector looks new, no corrosion.

Study the Forums, shop manual and electrical guides. Shop manual says IC pump is suppose to run in "power mode 6", or ignition on. This jives with what the wiring diagrams shows.
Troubleshooting procedure is to test the pump and look for electrical faults. Not super descriptive.
With ignition on I:
- Test for power across pump connector. Nothing.
- Test for power on both sides of fuse 24. Nothing.
- Test for power on some other fuses. Get 12V so my tester works and I have a good ground spot.
- Plug in the old pump. Pull fuse 24. Apply 12V to one leg in the fuse block - the pump runs. So it seems that the wiring from the fuse to the pump is OK.
- Apply 12V to the other leg, nothing, which is what I would expect.
- Check if either leg shows a path to ground. No, which is what I would expect

Per posts by @AlexJag @Justtttttom and a couple of other folks, relay 12B (which runs the pump) is apparently on the PC board under the fuses.
It looks like one pin of the low side of the relay is energized with ignition on, and the ECM provides a ground for the other low side pin, which activates the relay and connects ignition power at the high side to the pump.
I am really not up for taking my fuse box apart and troubleshooting 12B, for all I know the issue is the ECM and fixing the relay would do nothing.

Some posts (seems like mostly for pre 09 cars) suggest that the IC pump does not in fact run with ignition on. It's a quiet pump, and I cannot say whether it did on my car. But let's say it does only run with engine on and all of the above was a goose chase, what else would cause P2106..?

Sooo..
1) What am I missing?
2) Is my best option at this point to bypass the ECM feed for the IC pump and wire it "always on" with ignition?
3) Does the IC pump ever "run on" after hot shutdown? I know they do on other cars, have not noticed on the XKR..If so I would lose this with "always on"..

Thanks for reading-
Bob

 

Er... P2601 or P2106 ?

If P2601, it's usually related to the SC coolant pump (replace it) but just about could be the sensor, reliable though they seem to be.

 

2601- good catch, thanks. I don't seem to be able to edit it will keep trying.
I will replace the pump, but since per all my troubleshooting and bench testing
1) the pump works fine on the bench and 2) no voltage is being provided to the pump
.. I am not optimistic that replacing the pump alone will fix it.

You mention the "sensor".. what sensor, specifically, please?

thanks!
Bob

 

IAT2

measures air temp after SC & it's (hopefully) been cooled by the SC coolant stuff

 

Bob,

I've edited the P2106 typo in your post #1. Members have around 24 hours (depending on the time of day the post was made) to edit posts after which they become locked and only a moderator can apply edits.



P2601 is very specific and has no extended codes:
Coolant Pump Control Circuit Range/Performance - No sub type information

This is either a signal range or component failure. Coolant Pump A Control Circuit short to ground and short to battery both set different codes. (P2602-11 and P2603-12 respectively)

X150 is a sensitive beast. If you run an SDD session on an apparently normally performing example, it's unusual NOT to find a list of codes returned. These only become apparent when running a diagnostic session or when one of the codes is in the subset which set the CEL. Quite often it can simply be an out-of-range signal that has set a code. When I get an "unexpected" code, I generally first clear it and then run a couple of drive cycles to see if it returns before suspecting a physical fault (harness or component) It's more often been an out-of-range signal (temporary) than a failure (permanent). Nothing lost, apart from time with this approach and it frequently avoids replacing components or chasing phantoms.

Graham

 

Graham, @GGG thank you for fixing my typo.
Since my last post I have changed the coolant pump out for the Bosch type. No difference, CEL is still on. I have not driven the car as the undertray is still off, but I did run it for several minutes @ 2k rpm as part of the coolant bleed procedure. I am unclear if the coolant pump would be expected to come on or if the CEL would clear with this little bit of running. IAT got to 45C during this time, coolant to 91C. Maybe I should just button it back up and drive it...

I tested the coolant pump relay by grounding the white wire from the ECM to the relay. Relay clicks and pump comes on.

My Foxcon reader shows P2601 Pending and P2601 Permanent. It let me clear the Pending but not the Permanent. What does a "Permanent" code mean?

@JagV8 mentioned above that IAT2 may be suspect. I did some research and it seems that IAT2 is incorporated into the MAF? If they are indeed the same sensor, it may be relevant that the car threw a MAF code quite a few months ago, it ran like crap for a bit and then self cleared and has not reappeared.

I am open to suggestions as to next steps..
thx
Bob

 

I don't know whether P2601 can mean a 2nd IAT in a MAF - I'm doubtful so I'd want to find out for certain.

 

Far as I ever knew, there isn't an available IAT2 sensor and therefore no value.
I've been wrong before though (married four times).

 

Thinking aloud a bit here..
From the electrical guide, the image at the bottom is what led me to speculate that IAT is in with MAF..
But this feels like a rabbit hole.. I would be assuming that IAT tells the ECU to turn on the intercooler pump, then assuming that IAT is bad even though no codes..
But MAF is before the supercharger, right? So this would not be the right IAT, it wouldn't know what the post-charger temps were. And I find no references to other IATs in the forums or workshop manual or electrical guide.

ANWAY.. what would you guys do if this was your car? Barring a better idea, I am going to button it up and drive it a bit, while monitoring the temps. Maybe the old pump had an intermittent, and maybe a drive cycle or two with the new pump will get it happy again.

I would still like to know what a "Permanent" code indicates. Thank you for your help!
Bob

 

MAF/IAT is a combo unit.

 

"Permanent" code is one that has thrown a CEL. "Pending" hasn't had enough repeats or long enough occurrence to throw a light.

 

Well, here’s the latest, and hopefully final update.I put the under tray back on the car, and when I started it up, the CEL was out. I had previously not been able to make it reset with my code reader. The reader would say OK, but then, when I shut the car off and restarted it, the light was still on. Thinking back, I may not have shut the car completely down, or maybe it needs to sit for a few minutes, because all I did was let it sit for a couple days when I didn’t have time to work on it, and when I came back, the CEL was out.
A 1 hour test drive around town, along with some freeway time, and the CEL did not come back on. FWIW, I had the code, reader, hooked up, and here are the temps I was seeing.


When I got home, I thought I could hear the pump running when I got down by the front of the car. Next, I checked the pump side of fuse, 24 for voltage, and it was showing 12 V. It would not do this with the key on, and with the car cold.

So,to re-state everything a bit, with ignition on, the high and low side of the relay are provided with power. When the ECM decides it is necessary, it provides a ground for the low side of the relay, then the pump runs.It appears that my concern that the pump wasn’t running with key on, when the car was cold, was unfounded and resulted in a bit of a rabbit hole.

For what it’s worth, I did confirm that the wiring from the relay to the pump, the relay itself, and the relay function when the ECM is providing a ground, were all in good shape. So if the problem recurs, I know it’s none of that stuff.

As others predicted, and thank you again by the way, the problem seems to have been exclusively the pump. I still don’t know why the pump ran fine on the bench when provided 12 V, maybe it has a problem when it gets hot, maybe it’s weak or something. I took it apart out of curiosity, and there were no obvious problems. there is a magnetic coupling between the motor and the impeller, which is kind of a cool way to keep everything, sealed, and moisture away from the motor bearings.



One last item of note, I bench tested the Bosch pump before I installed it, and it sounded like hell on the bench. Like it had a bad bearing or something. I only ran it for a second or two, suspecting that it wanted coolant for lubrication. That is the case, it is extremely quiet in the car.

I won’t be completely completely confident that it’s cured until I get a couple hours on the open road logged, but things are looking good for now. Thanks again for everyone’s help.
Bob.

 

That inlet air temp looks way way high at 73 C I'm not sure that is the reading at the combo MAF/IAT (located above the air filter box) it should be reading around the ambient minus whatever cooling effect of the air flow across it..

 

I don’t know what sensor that reading is from. I assume it is post-supercharger, there must be a sensor that gives post boost air temp to the ECM. But I don’t know. Agreed that it’s too high to be from the combo unit.

 

Some of the things the PCM relies on are temperature sensors (& the differences between them).

It also monitors warm ups (engine going from temperature cold enough to warm enough).

Many codes by law flag only after 2 warm ups (& self-clear after 4).

You don't want any dubious sensors.

 

I recently replaced my Bosch 010 with ZZP pump. ZZP HIGH OUTPUT INTERCOOLER PUMP - STAGE 1 https://a.co/d/08a2OqC9

After an initial test drive...so far so good. It's on a 2010 XKR.