‘15 Passat Coolant pump fault

Can y’all help me understand what this is and how to fix it? And do you know if it’s covered under the dieselgate extended warranty? I cleared it once but it’s come back. Then cleared it a 2nd time and haven’t seen anything yet... but only have 7miles since last clear.


1 Fault Found:
28388 - Coolant Pump 3
P26F4 00 [175] - Electrical Malfunction / Open Circuit
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 229774 km
Date: 2020.01.07
Time: 22:46:32

Engine speed: 831.00 /min
Normed load value: 28.6 %
Vehicle speed: 0 km/h
Coolant temperature: 48 °C
Intake air temperature: 28 °C
Ambient air pressure: 1000 mbar
Voltage terminal 30: 13.880 V
Unlearning counter according OBD: 40
Heater support pump 1 bank 1 second.circuit: activat.: 94.79 %
Extern.temp.sens.1 bank 1: raw value: 9.5 °C
Shut-off timer: last engine shut-off time: 25393 s

Readiness: 1 1 0 0 1


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While I am not 100% sure, but if it's an electrical issue, it may not be covered by Dieselgate warranty.

tdi54 said:

While I am not 100% sure, but if it's an electrical issue, it may not be covered by Dieselgate warranty.

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Any idea where it’s located? I’m having trouble finding good videos on YouTube.


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Bump. Anyone’s got any advice?


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See if you can find a schematic of the cooling system. You might have either a connector that has come loose or a wire that has chafed through near the pump. If you keep driving the vehicle keep a close eye on coolant temps, you do not want to make things worse with an overheating episode.

Tom in PT said:

See if you can find a schematic of the cooling system. You might have either a connector that has come loose or a wire that has chafed through near the pump. If you keep driving the vehicle keep a close eye on coolant temps, you do not want to make things worse with an overheating episode.

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Ya the light is still on. No cooling issues yet. Do you know where this cooling pump is located? I believe it’s an electric auxiliary pump. Possibly to help with emissions and not actually engine oil or trans fluid cooling.


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The charge air cooler coolant circuit pump gets unplugged during an oil change to not get drenched in oil from the filter. Have seen that electrical connector just loose or not connected at all after an oil change. That would be my first place to check, could just be a loose connector on the pump.

adjat84th said:

The charge air cooler coolant circuit pump gets unplugged during an oil change to not get drenched in oil from the filter. Have seen that electrical connector just loose or not connected at all after an oil change. That would be my first place to check, could just be a loose connector on the pump.

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I was able to find it. Looks like when I replace the swaybar, the pump on the backside somehow got disconnected. So i plugged it back in. But funny you mention the oil on the front plug, cause that thing is covered in oil.


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Guys

I’m wondering if something is wrong with mine. From my Torque app I see huge variations in inlet temp- from 80-180 F from downhill to uphill. Flat cruising is around 107 on a 40 degree day.

I thought the computer targeted an intake temp of 128 f. This is never near that. I checked and my pump is indeed plugged in.

Is this normal? I hope thought the whole point of the water to air intercooler was to stabilize peaks and valleys at 128 or so.

Marc O

2snakes said:

Guys



I’m wondering if something is wrong with mine. From my Torque app I see huge variations in inlet temp- from 80-180 F from downhill to uphill. Flat cruising is around 107 on a 40 degree day.



I thought the computer targeted an intake temp of 128 f. This is never near that. I checked and my pump is indeed plugged in.



Is this normal? I hope thought the whole point of the water to air intercooler was to stabilize peaks and valleys at 128 or so.



Marc O

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You sure you're monitoring the correct sensor? There are pre and post cooler sensors.
Mine at full power peaks around 135F, then comes down pretty quickly to 105-115F cruising. A very flat curve even when pushing to ~110mph during some datalogging runs.



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adjat84th,
I'm measuring it out of Torque, so it doesn't show me measuring blocks. I do have Ross-Tech VCDS so I'll measure out of there next.
What measuring blocks have the intake temps before and after the intercooler?
Thanks!
Marc O

I always use advanced measuring blocks channel which you can search sensors by name. I don't search by block/group. Charge air cooler can be viewed as pre/post though in the same line if you wish.

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Standard vanilla torque temps are junk, it'll tell you your trany temp is the same as your coolant, which it's not, easy verified during cold start up.

Also I've seen charge coolant temps stick around 200-240 after long highway runs and she's nice and heat soaked.