Second coolant sensor measuring block missing (G62, Phaeton V8)

[invisiblewave]

I'd been getting implausible signal/signal too high indications from my cooling system for a couple of years, but only in winter. When it first happened, I scanned the car and watched what I thought were the two coolant sensors, and it showed both rising from cold, pointing to a thermostat stuck in the open position. I'd been waiting on a timing belt change to do the thermostat, but at the weekend decided to change the G62 anyway. I changed it, reset the CEL, and it solved the problem. I then scanned all 10 coolant labels on the test drive and all of them started rising from cold. I think this means that I'm unable to see the G62 from VCDS.

 

[jyoung8607]

Hey hey, a veteran member of Team Phaeton! Auto-Scans are usually nice for this sort of thing, but I think I have data for this ECU anyway. I honestly don't remember what (if anything) the V8 ECU does in response to the other temp sensor input; I feel like the V8 didn't have a map-controlled thermostat.

Unfortunately I don't have a saved map that I can find from my parts V8 I owned for awhile. For now, try looking in the MVBs between 130 and 136 for engine cooling related stuff. You'll have at least some documented data in that range, and for the V8 undocumented MVBs 130 and 131, you *may* show data the same way the W12 does, just maybe without thermostat duty cycle. Note the engine outlet vs radiator outlet temps, I believe those will show your two coolant temp sensors independently.

If that doesn't work, post a control channel map in CSV format for Engine-01 and we'll see what we can find together.

V8 engine cooling:

130,0,Undocumented
;
131,0,Undocumented
;
132,0,Map cooling
132,4,Status cooling,see label
;1 = Description fulfilled / 0 = Description not fulfilled
;X0000000 not used
;0X000000 not used
;00X00000 Fan stage 1 active
;000X0000 Fan stage 2 active
;0000X000 Control deviation (0 > specified temp. / 1 < specified temp.)
;00000X00 Cooling van triggering active
;000000X0 Thermostat actuation active
;0000000X Error in system
;
133,0,Undocumented
;
134,0,Temperature
134,1,Oil,temperature
134,2,Ambient,temperature
134,3,Intake air,temperature
134,4,Engine outlet,temperature
;
135,0,Coolant fan control short trip
135,2,Duty cycle,stage 1
135,3,Duty cycle,stage 2
;
136,0,Activities after Engine Shutdown
136,3,Aux Water Pump,status
136,4,After-run,coolant fan

W12 engine cooling:

130,0,Coolant Flow Characteristics
130,1,Coolant at,engine output
130,2,Coolant at,radiator output
130,3,Duty cycle,of thermostat
130,4,Not Used
;
131,0,Coolant Flow Characteristics
131,1,Coolant at,engine output
131,2,Specified engine,output temperature
131,3,Coolant at,radiator output
131,4,Duty cycle,of thermostat
;
132,0,Coolant Flow Characteristics
132,1,Specified radiator,output temperature
132,2,Delta Temperature,engine vs. rad outputs
132,3,
132,4,Cooling,status
;
133,0,Not used - next measuring block used is 134
;
134,0,Engine Cooling Related Values
134,1,Oil,Temperature
134,2,Ambient Air,Temperature
134,3,Inlet Air,Temperature
134,4,Engine output,Temperature
;
135,0,Engine Cooling Related Values
135,1,Current Radiator,output temperature
135,2,Duty cycle,Fan 1 activation,Range:15 - 95%
135,3,Duty cycle,Fan 2 activation,Range:15 - 95%
135,4,Powertrain coolant,fan temperature
;
136,0,Engine Cooling Related Values
136,1,Unknown
136,2,Unknown
136,3,Auxiliary water,pump status,Values: on or off
136,4,After-Run Coolant,Fan control status,Values: on or off

 

[Uwe]

This does not belong in Product Support.. Moving to Car Repair Support.

-Uwe-

 

[invisiblewave]

Thanks Jason! I don't understand most of that. I haven't spent much time with the software since I only use it on the rare occasions my Phaeton has an issue. I'm using the Android app, and all I see is a list of measurable values with a description and a number, there's no "block" as far as I can see, like 4 or 5 values within a block of 132.

 

[invisiblewave]

This does not belong in Product Support.. Moving to Car Repair Support.

-Uwe-

I spent quite a long time trying to decide where to post this based on the rules. It's car-specific, but is about an apparent gap in what the product supports for that car.

 

[Uwe]

It's car-specific, but is about an apparent gap in what the product supports for that car.

VCDS can only show you what the car is willing to tell it.

-Uwe-