# P0117,P1672 & High Pressure Sensor (G65) faults



## ebi718 (Jan 16, 2011)

Hello, I replaced a faulty electric cooling fan (passenger side) recently on my C5 A6 3.0L yesterday and pulled these codes today. A/C blows well, without issue. In order to troubleshoot these faults some more, I did some logging off VCDS. I noticed that if I turn ECON mode on (the AC compressor shuts off which is normal, thus no more cold air), BUT the coolant temperature starts to rise.. from 90s up to 106+, until I turn ECON mode off. Note: this is the value off VCDS; the coolant temp guage remains at 12 o'clock.

I cleared the P0117 fault but it returned soon after. Another concern I have is why the after-run cooling system doesn't work. Even when the coolant temp is close to 105, I have never heard the fan come on after switching off the engine. Any ideas why this is?

Ps: These faults (P0117,P1672 & High Pressure Sensor (G65) faults) came up only after the new fan was put in.

Thanks in advance.


```
Wednesday,04,July,2012,03:11:32:49820
VCDS Version: Release 11.11.3
Data version: 20120401



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--------------------------------------------------------------------------------


Chassis Type: 4B - Audi A6 C5
Scan: 01 02 03 06 08 15 16 17 18 22 34 35 36 37 45 55 56 57 65 67
          75 76 77
 
VIN: WAUxxx
-------------------------------------------------------------------------------
Address 01: Engine        Labels: 06C-909-559-ASN.lbl
   Part No SW: 8E0 909 559 R    HW: 8E0 909 059 
   Component: 3.0L V6/5V      G   0020  
   Coding: 0016752
   Shop #: WSC 02334 785 00200
   VCID: 448DB2C00480FE9

1 Fault Found:
[B]18080 - Coolant Fan Control 1 [/B]
            P1672 - 004 - Open or Short to Ground - Intermittent
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 02: Auto Trans        Labels: 01V-927-156.lbl
   Part No: 4B0 927 156 FF
   Component: AG5 01V 3.0l5V  USA 1213  
   Coding: 0001002
   Shop #: WSC 02334 785 00200
   VCID: 70E52E1060B8329

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 4B0-614-517.lbl
   Part No: 4B0 614 517 H
   Component: ABS/ESP allrad      3428  
   Coding: 06497
   Shop #: WSC 02334  
   VCID: 26490848C2FC2C9

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC        Labels: 4B0-820-043-MY2.lbl
   Part No: 4B0 820 043 AR
   Component: A6-Klimavollautomat 0208  
   Coding: 00110
   Shop #: WSC 02335  
   VCID: 6AD13C781664C89

1 Fault Found:
[B]00819 - High Pressure Sensor (G65) 
            30-10 - Open or Short to Plus - Intermittent[/B]

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: None
   Part No: 4B0 959 655 AB
   Component: Airbag 8.4EP        1001  
   Coding: 0000607
   Shop #: WSC 02334 785 00200
   VCID: 70E52E1060B8329

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 4B0-907-487.lbl
   Part No: 4B0 907 487 F
   Component: Lenkradelektronik   D01   
   Coding: 01002
   Shop #: WSC 02334  
   VCID: 2F67ED6CED066D1

6 Faults Found:
01305 - Databus for Infotainment 
            37-10 - Faulty - Intermittent
01305 - Databus for Infotainment 
            80-10 - Single-Wire Operation - Intermittent
01305 - Databus for Infotainment 
            49-10 - No Communications - Intermittent
00480 - Control Module in Instruments for Infotainment CAN (J285) 
            27-10 - Implausible Signal - Intermittent
00480 - Control Module in Instruments for Infotainment CAN (J285) 
            49-10 - No Communications - Intermittent
01304 - Radio 
            49-00 - No Communications

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 4B0-920-xxx-17.lbl
   Part No: 4B0 920 983 E
   Component: KOMBI+WEGFAHRS. VDO D16  
   Coding: 16262
   Shop #: WSC 03285  
   VCID: 2A51FC78D6E4089
   WAUVT64B24N089300     AUZ7Z0D2601657

1 Fault Found:
01304 - Radio 
            49-00 - No Communications

-------------------------------------------------------------------------------
Address 35: Centr. Locks        Labels: 4B0-962-258.lbl
   Part No: 4B0 962 258 M
   Component: Central Lock/Alarm  D38  
   Coding: 15885
   Shop #: WSC 02334  
   VCID: 336FE11C012E491

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr        Labels: None
   Part No: 4B0 959 760 B
   Component: Sitzmemory R1 F     0204  
   Coding: 00001
   Shop #: WSC 00000  
   VCID: 2C5DFA60DC10169

No fault code found.

End   ---------------------------------------------------------------------



Chassis Type: 4B - Audi A6 C5
Scan: 01 02 03 06 08 15 16 17 18 22 34 35 36 37 45 55 56 57 65 67
          75 76 77
 
VIN: WAUxxxx 
-------------------------------------------------------------------------------
Address 01: Engine        Labels: 06C-909-559-ASN.lbl
   Part No SW: 8E0 909 559 R    HW: 8E0 909 059 
   Component: 3.0L V6/5V      G   0020  
   Coding: 0016752
   Shop #: WSC 02334 785 00200
   VCID: 448DB2C00480FE9

1 Fault Found:
[B]16501 - Engine Coolant Temp. Sensor (G62) 
            P0117 - 001 - Signal too Low[/B]
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 02: Auto Trans        Labels: 01V-927-156.lbl
   Part No: 4B0 927 156 FF
   Component: AG5 01V 3.0l5V  USA 1213  
   Coding: 0001002
   Shop #: WSC 02334 785 00200
   VCID: 70E52E1060B8329

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes        Labels: 4B0-614-517.lbl
   Part No: 4B0 614 517 H
   Component: ABS/ESP allrad      3428  
   Coding: 06497
   Shop #: WSC 02334  
   VCID: 26490848C2FC2C9

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags        Labels: None
   Part No: 4B0 959 655 AB
   Component: Airbag 8.4EP        1001  
   Coding: 0000607
   Shop #: WSC 02334 785 00200
   VCID: 70E52E1060B8329

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel        Labels: 4B0-907-487.lbl
   Part No: 4B0 907 487 F
   Component: Lenkradelektronik   D01   
   Coding: 01002
   Shop #: WSC 02334  
   VCID: 2F67ED6CED066D1

6 Faults Found:
01305 - Databus for Infotainment 
            37-10 - Faulty - Intermittent
01305 - Databus for Infotainment 
            80-10 - Single-Wire Operation - Intermittent
01305 - Databus for Infotainment 
            49-00 - No Communications
00480 - Control Module in Instruments for Infotainment CAN (J285) 
            27-10 - Implausible Signal - Intermittent
00480 - Control Module in Instruments for Infotainment CAN (J285) 
            49-10 - No Communications - Intermittent
01304 - Radio 
            49-00 - No Communications

-------------------------------------------------------------------------------
Address 17: Instruments        Labels: 4B0-920-xxx-17.lbl
   Part No: 4B0 920 983 E
   Component: KOMBI+WEGFAHRS. VDO D16  
   Coding: 16262
   Shop #: WSC 03285  
   VCID: 2A51FC78D6E4089
   WAUVT64B24N089300     AUZ7Z0D2601657

1 Fault Found:
01304 - Radio 
            49-00 - No Communications

-------------------------------------------------------------------------------
Address 35: Centr. Locks        Labels: 4B0-962-258.lbl
   Part No: 4B0 962 258 M
   Component: Central Lock/Alarm  D38  
   Coding: 15885
   Shop #: WSC 02334  
   VCID: 336FE11C012E491

No fault code found.

-------------------------------------------------------------------------------
Address 36: Seat Mem. Drvr        Labels: None
   Part No: 4B0 959 760 B
   Component: Sitzmemory R1 F     0204  
   Coding: 00001
   Shop #: WSC 00000  
   VCID: 2C5DFA60DC10169

No fault code found.

End   --------------
```


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## ebi718 (Jan 16, 2011)

Thoughts? Anyone?

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## Anony00GT (Mar 6, 2002)

Do the fans turn on when you turn the A/C on (ECON off)?


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## ebi718 (Jan 16, 2011)

Yes, the fans do turn on. A/C works - blows cold air with out issue. The shop that installed the replacement (Aux electric) fan advised I get a new ECT sensor, that it may be root cause.


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## Anony00GT (Mar 6, 2002)

I guess the 18080 code was before fan replacement then?

Yes, check the ECT sensor. Does the engine ever actually overheat, or just hit 106 in measuring blocks?


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## ebi718 (Jan 16, 2011)

The 18080 code was AFTER the fan replacement.

This is a reading off the measuring blocks from yesterday. You see the ECT returning 105 C, however the guage is still at 12 oclock while idling @ 720rpm. One hunch is the ECT is faulty so it is returning way-off numbers. Another test (to confirm the state of the ECT) was to compare the reading of the IAT - intake air temperature - vs that of the ECT on a cold engine with key on engine off. I understand both should normally match. In this case, ECT was 32, while IAT was 34 which susgests replacing it.










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## Anony00GT (Mar 6, 2002)

Double-check the connections at the fan and temp sensor.

2 degrees difference is acceptable between IAT and ECT when cold.

Watch ECT values in the cluster (address 17) and compare to the value in 01. Also, 105*C = 221*F. I would consider that an acceptable temp as well, probably not even enough to move the needle past center.

How hot does it get at its hottest point? Have you let it get hot enough for the fans to turn on by themselves with the A/C off?


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## ebi718 (Jan 16, 2011)

I will doublecheck as suggested including monitoring the values @ address #17. I have never seen the reading cross 107 C. Infact (since the new fan went in) I have never allowed it to go past 106 - I usually turn on the A/C so the fans then go on highspeed which cools things down; if the engine temp is hot enough, they both come on but at low speed. I think that's the next test I will do... watch the temp go up, and wait for the fans to go on high-speed. Btw, at what temp are the fans supposed to switch to high speed? And what is the 'threshhold' value that definitively says 'overheating'? Past 110 C? Thanks


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## Anony00GT (Mar 6, 2002)

I don't know offhand what temp the fans come on high, you'll be able to find that in the service manual.

As a general rule of thumb, I'd consider too hot to be 111+*C.


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## ebi718 (Jan 16, 2011)

Anony00GT said:


> I don't know offhand what temp the fans come on high, you'll be able to find that in the service manual.
> 
> As a general rule of thumb, I'd consider too hot to be 111+*C.


I see in Bentley Service Manual: 2 stage fan switch (F54)

STAGE 1 switching temps
On: 92 - 97 C (198 - 207F) 
off: 84 - 91 C (83 - 196F)

STAGE 2 switching temps
on:99 - 105 C(210 - 221F)
off:91 - 98 C (196 - 208F)


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## Anony00GT (Mar 6, 2002)

There you go.

Keep in mind, the fan switch is in the lower radiator hose. That doesn't see the same temp as the combination sensor you're watching in 01 and 17, the blocks generally read hotter.


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## ebi718 (Jan 16, 2011)

Problem fixed. Installed new green ECT sensor, cleared codes..faults haven't returned. :thumbup:


Thanks.

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