# 2008 Jetta 2.5L - Engine temperature warning light despite normal engine temperature values



## alexgc (Feb 13, 2010)

A co-worker's 2008 2.5L Jetta is throwing an engine temperature warning light upon engine start for the last 4 mornings. She stated that it ONLY occurs in the morning and not at any other time of the day. When the ignition is cycled, the warning light goes away. I logged block 001-2 in the Engine control module and it gave me coolant temp readings of between 85-87 C. No fault codes were present in the Engine or Instrument control modules either. Suggestions of what else to check/log would be appreciated. :thumbup:

Screen shot of dash with warning light:










And the full ECU scan:


Friday,14,September,2012,09:32:31:53151
VCDS Version: Release 11.11.4
Data version: 20120807



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


Chassis Type: 1K0
Scan: 01 02 03 08 09 0F 15 16 17 19 25 42 44 46 52 56 62 65 72

VIN: 3VWRZ71K98M032392 Mileage: 137440km/85401miles

01-Engine -- Status: OK 0000
02-Auto Trans -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
0F-Digital Radio -- Status: Malfunction 0010
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: OK 0000
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
56-Radio -- Status: Malfunction 0010
62-Door, Rear Left -- Status: OK 0000
65-Tire Pressure -- Status: Malfunction 0010
72-Door, Rear Right -- Status: OK 0000

-------------------------------------------------------------------------------
Address 01: Engine (CBU) Labels: 06A-906-032-BGP.lbl
Part No SW: 07K 906 032 BG HW: 07K 906 032 Q
Component: 2,5l R5/4V G 1565 
Revision: 1NH01--- Serial number: VWX7Z0G724D0SK
Coding: 0000003
Shop #: WSC 00066 000 00000
VCID: 6FED69ED7E529360C8F

No fault code found.
Readiness: 0000 1000

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 09G-927-750.lbl
Part No SW: 09G 927 750 HE HW: 09G 927 750 HE
Component: AQ 250 6F 1090 
Revision: 00H69000 Serial number: 
Coding: 0000584
Shop #: WSC 00066 000 00000
VCID: 7BF54DBD3A2AFFC0747

No fault code found.

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 1K0-907-379-MK60-F.lbl
Part No SW: 1K0 907 379 AC HW: 1K0 907 379 AC
Component: ESP FRONT MK60 0101 
Revision: 00H11001 
Coding: 0021122
Shop #: WSC 00066 000 00000
VCID: 73E5659D127AB7802C7

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 1K0-820-047.lbl
Part No SW: 1K0 820 047 GG HW: 1K0 820 047 GG
Component: Climatic PQ35 141 0909 
Revision: 00141027 Serial number: 00000000000000
Shop #: WSC 00000 000 00000
VCID: 6FED69ED7E529360C8F

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 3C0-937-049-30-M.lbl
Part No SW: 3C0 937 049 AH HW: 3C0 937 049 AH
Component: Bordnetz-SG H54 2202 
Revision: 00H54000 Serial number: 00000000711073
Coding: 04058E234004150007140000001400008008730B5C000100000000000000
Shop #: WSC 00066 000 00000
VCID: 6FED69ED7E529360C8F

Subsystem 1 - Part No: 1K1 955 119 E Labels: 1KX-955-119.CLB
Component: Wischer 080207 020 0501 
Coding: 00038805
Shop #: WSC 00066 

No fault code found.

-------------------------------------------------------------------------------
Address 0F: Digital Radio Labels: 8E0-035-593-SIR.lbl
Part No SW: 8E0 035 593 H HW: 8E0 035 593 H
Component: SDAR SIRIUS H06 0080 
Revision: 00000000 Serial number: AUZ4Z7G0128306
Shop #: WSC 00000 000 00000
VCID: 2E53B4E9B9D8DA68839

2 Faults Found:
02635 - Tuner Not Enabled/Activated 
000 - - 
Freeze Frame:
Fault Status: 01100000
Fault Priority: 7
Fault Frequency: 1
Reset counter: 8
Mileage: 137324 km
Time Indication: 0
Date: 2000.00.00
Time: 06:18:24

02788 - Internal Communications Error 
000 - - 
Freeze Frame:
Fault Status: 01100000
Fault Priority: 7
Fault Frequency: 18
Reset counter: 10
Mileage: 137445 km
Time Indication: 0
Date: 2000.00.00
Time: 21:12:27

Freeze Frame:
Bin. Bits: 00000000
Bin. Bits: 00000001


-------------------------------------------------------------------------------
Address 15: Airbags Labels: 1K0-909-605.lbl
Part No SW: 1K0 909 605 AB HW: 1K0 909 605 AB
Component: 6A AIRBAG VW8R 034 8000 
Revision: 05034000 Serial number: 003B6M02MAH7 
Coding: 0013889
Shop #: WSC 00066 000 00000
VCID: 6CD77EE14F446878EDD

Part No: 1K0 959 339 F
Component: BF-Gewichtsens. 007 0005

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 1K0-953-549-MY8.lbl
Part No SW: 1K0 953 549 AP HW: 1K0 953 549 AP
Component: Lenksäulenmodul 036 0070 
Coding: 0010021
Shop #: WSC 00066 000 00000
VCID: 800FBA51D3CC1C18A15

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 1K0-920-xxx-17.lbl
Part No SW: 1K0 920 954 SX HW: 1K0 920 954 SX
Component: KOMBIINSTRUMENT 3HL 1222 
Revision: V0005000 Serial number: VWX7Z0G724D0SK
Coding: 0023203
Shop #: WSC 06485 444 64721
VCID: 94278601B7B490B815D

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 1K0-907-530-V3.clb
Part No SW: 1K0 907 530 L HW: 1K0 907 951 
Component: J533 Gateway H07 0052 
Revision: H07 01 Serial number: 100707F2000029
Coding: ED807F070003021002
Shop #: WSC 00066 000 00000
VCID: 306FAA91A3ECCC98915

No fault code found.

-------------------------------------------------------------------------------
Address 25: Immobilizer Labels: 1K0-920-xxx-25.clb
Part No SW: 1K0 920 954 SX HW: 1K0 920 954 SX
Component: IMMO 3HL 1222 
Revision: V0005000 Serial number: VWX7Z0G724D0SK
Shop #: WSC 06485 444 64721
VCID: 94278601B7B490B815D

No fault code found.

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver Labels: 1K0-959-701-MIN3.lbl
Part No SW: 1K0 959 701 P HW: 1K0 959 793 L
Component: J386 TUER-SG FT 1133 
Revision: 32008001 Serial number: 00000056478727
Coding: 0001205
Shop #: WSC 00066 000 00000
VCID: 3B758DBD7AAA3FC0347

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist Labels: 1Kx-909-14x-44.clb
Part No: 1K1 909 144 M
Component: EPS_ZFLS Kl.070 H08 1901 
Shop #: WSC 02069 000 90108
VCID: 35619B855C8EE9B0C23

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 1K0-959-433-MAX.clb
Part No SW: 1K0 959 433 CT HW: 1K0 959 433 CT
Component: KSG PQ35 RDK 052 0221 
Revision: 00052000 Serial number: 00000000000000
Coding: 13900F880186483F2D04058FB0880F0488DCA0
Shop #: WSC 00066 000 00000
VCID: 8407B641C7D4003885D

Component: Sounder n.mounted 

Component: NGS n.mounted 

Component: IRUE n.mounted 

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. Labels: 1K0-959-702-MIN3.lbl
Part No SW: 1K0 959 702 P HW: 1K0 959 792 L
Component: J387 TUER-SG BT 1133 
Revision: 32008001 Serial number: 00000045778727
Coding: 0001204
Shop #: WSC 00066 000 00000
VCID: 3C778EA17FA438F83DD

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 1K0-035-1xx-56.lbl
Part No SW: 1K0 035 180 L HW: 1K0 035 180 L
Component: Radio DE2 016 0020 
Revision: 00016000 Serial number: VWZ4Z7G2161031
Coding: 0010400
Shop #: WSC 00000 000 00000
VCID: 295947F58036BD5056B

3 Faults Found:
00856 - Radio Antenna 
011 - Open Circuit
01044 - Control Module Incorrectly Coded 
000 - - 
00003 - Control Module 
014 - Defective

-------------------------------------------------------------------------------
Address 62: Door, Rear Left Labels: 1K0-959-703-GEN3.lbl
Part No SW: 1K0 959 703 Q HW: 1K0 959 795 J
Component: J388 TUER-SG HL 1120 
Revision: 12006001 Serial number: 00000001956673
Coding: 0001168
Shop #: WSC 00066 000 00000
VCID: 3E7384A969B82AE8139

No fault code found.

-------------------------------------------------------------------------------
Address 65: Tire Pressure Labels: 3C0-959-433-65.lbl
Part No SW: 1K0 959 433 CT HW: 1K0 959 433 CT
Component: RDK 0450 
Revision: 00052000 Serial number: 00000000000000
Coding: 0100101
Shop #: WSC 00066 000 00000
VCID: 8407B641C7D4003885D

1 Fault Found:
01521 - Sensor for Tire Pressure 
004 - No Signal/Communication - Intermittent
Freeze Frame:
Fault Status: 00110100
Fault Priority: 4
Fault Frequency: 2
Reset counter: 49
Mileage: 137429 km
Time Indication: 0
Date: 2000.00.00
Time: 07:12:59


-------------------------------------------------------------------------------
Address 72: Door, Rear Right Labels: 1K0-959-704-GEN3.lbl
Part No SW: 1K0 959 704 Q HW: 1K0 959 794 J
Component: J389 TUER-SG HR 1120 
Revision: 12006001 Serial number: 00000001939101
Coding: 0001168
Shop #: WSC 00066 000 00000
VCID: 3F8DF9AD6EB223E018F

No fault code found.

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


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## Anony00GT (Mar 6, 2002)

Coolant level full?


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## alexgc (Feb 13, 2010)

Anony00GT said:


> Coolant level full?


Yup, first thing we looked at - level is in the expected range.


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## VR6Now (Dec 31, 2000)

Air trapped in coolant loop?


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## alexgc (Feb 13, 2010)

VR6Now said:


> Air trapped in coolant loop?


Could be possible - how can I check or look for that?


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## VR6Now (Dec 31, 2000)

I would just bleed the system and see if the problem goes way. My next concern would be how it got there (Head Gasket? Warped head? Botched flush job? Bad radiator cap?)

It could also be just be a faulty thermostat or wiring fault.


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## alexgc (Feb 13, 2010)

VR6Now said:


> I would just bleed the system and see if the problem goes way. My next concern would be how it got there (Head Gasket? Warped head? Botched flush job? Bad radiator cap?)
> 
> It could also be just be a faulty thermostat or wiring fault.


Can the thermostat state be monitored through some VCDS block #?


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## VR6Now (Dec 31, 2000)

You can monitor your coolant temperature sensor. I think this is going to require 'old fashion' troubleshooting and diagnosis skills to chase down. Is the water pump making any noises when cold? Is there water/coolant on the oil dipstick?


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## alexgc (Feb 13, 2010)

VR6Now said:


> You can monitor your coolant temperature sensor. I think this is going to require 'old fashion' troubleshooting and diagnosis skills to chase down. Is the water pump making any noises when cold? Is there water/coolant on the oil dipstick?


OK, I was thinking of attempting to monitor the coolant temperature sensor when she starts her engine immediately in the morning. She is going to have the system flushed and refilled first, so lets see where that leaves us.


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## VR6Now (Dec 31, 2000)

Before doing anything, I would asses the condition of the vehicle. Excessive moisture in exhaust, moisture in crank, rough idle, water pump quiet? Then I would scan for codes (and you did)

I'm just stabing completely in the dark because little is known. You scanned the car and got nothing so looking at scans and logs may not disclose the complete story. I would check the car before doing anything else.

There's no harm in monitoring the coolant temperature sensor before start up until warm up to see if any implasible values are returned.


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## haskie (Mar 6, 2011)

VR6Now said:


> Before doing anything, I would asses the condition of the vehicle. Excessive moisture in exhaust, moisture in crank, rough idle, water pump quiet? Then I would scan for codes (and you did)
> 
> I'm just stabing completely in the dark because little is known. You scanned the car and got nothing so looking at scans and logs may not disclose the complete story. I would check the car before doing anything else.
> 
> There's no harm in monitoring the coolant temperature sensor before start up until warm up to see if any implasible values are returned.


sorry to bring this back from the dead, but did you resolve this? what was the cause? I'm having the same issue - cycle the ignition after warm up and she's happy again.


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## stan067 (Feb 25, 2010)

Full updated auto scan first then you get replies.

It's a rule for this forum.

Good Luck


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## haskie (Mar 6, 2011)

stan067 said:


> Full updated auto scan first then you get replies.
> 
> It's a rule for this forum.
> 
> Good Luck


gotcha.

Saturday,10,January,2015,11:28:22:12914
VCDS -- Windows Based VAG/VAS Emulator
VCDS Version: 14.10.0.0
Data version: 20141022


VIN: 3VW License Plate: 
Mileage: 200130km-124355mi Repair Order: 



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


Chassis Type: 1K (1K0)
Scan: 01 03 08 09 0F 15 16 17 19 25 42 44 46 52 56 62 65 72

VIN: 3VW Mileage: 200130km-124355miles

01-Engine -- Status: OK 0000
03-ABS Brakes -- Status: OK 0000
04-Steering Angle -- Status: OK 0000
08-Auto HVAC -- Status: OK 0000
09-Cent. Elect. -- Status: OK 0000
0F-Digital Radio -- Status: Malfunction 0010
15-Airbags -- Status: OK 0000
16-Steering wheel -- Status: Malfunction 0010
17-Instruments -- Status: OK 0000
19-CAN Gateway -- Status: OK 0000
25-Immobilizer -- Status: OK 0000
42-Door Elect, Driver -- Status: OK 0000
44-Steering Assist -- Status: OK 0000
46-Central Conv. -- Status: OK 0000
52-Door Elect, Pass. -- Status: OK 0000
56-Radio -- Status: OK 0000
62-Door, Rear Left -- Status: OK 0000
65-Tire Pressure -- Status: OK 0000
72-Door, Rear Right -- Status: OK 0000

-------------------------------------------------------------------------------
Address 01: Engine (CBU) Labels: 06A-906-032-BGP.lbl
Part No SW: 07K 906 032 BH HW: 07K 906 032 Q
Component: 2,5l R5/4V G 1566 
Revision: 1NH01--- Serial number: VWX7Z0GN24H099
Coding: 0000001
Shop #: WSC 00066 000 00000
VCID: 70C1388C639161A19FB-8025

No fault code found.
Readiness: 0000 0000

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 1K0-907-379-MK60-F.lbl
Part No SW: 1K0 907 379 AC HW: 1K0 907 379 AC
Component: ESP FRONT MK60 0101 
Revision: 00H11001 
Coding: 0021122
Shop #: WSC 00066 000 00000
VCID: 73CB378012875AB9629-8026

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 1K0-820-047.lbl
Part No SW: 1K0 820 047 GG HW: 1K0 820 047 GG
Component: Climatic PQ35 141 0909 
Revision: 00141027 Serial number: 00000000000000
Shop #: WSC 00000 000 00000
VCID: 6FC33BF07EAF7E59861-803A

No fault code found.

-------------------------------------------------------------------------------
Address 09: Cent. Elect. Labels: 3C0-937-049-30-M.lbl
Part No SW: 3C0 937 049 AH HW: 3C0 937 049 AH
Component: Bordnetz-SG H54 2202 
Revision: 00H54000 Serial number: 00000000801764
Coding: 04058C234004150007140000001400000008730B5C000100000000000000
Shop #: WSC 00066 123 12345
VCID: 6FC33BF07EAF7E59861-803A

Subsystem 1 - Part No: 1K1 955 119 E Labels: 1KX-955-119.CLB
Component: Wischer 221107 021 0501 
Coding: 00038805
Shop #: WSC 00066 

No fault code found.

-------------------------------------------------------------------------------
Address 0F: Digital Radio Labels: 8E0-035-593-SIR.lbl
Part No SW: 8E0 035 593 H HW: 8E0 035 593 H
Component: SDAR SIRIUS H06 0080 
Revision: 00000000 Serial number: AUZ4Z7G0197822
Shop #: WSC 00000 000 00000
VCID: 2E7DE6F4B9253751CD7-807B

1 Fault Found:
02635 - Tuner Not Enabled/Activated 
000 - - 
Freeze Frame:
Fault Status: 01100000
Fault Priority: 7
Fault Frequency: 3
Reset counter: 249
Mileage: 196118 km
Time Indication: 0
Date: 2000.00.00
Time: 00:07:46


-------------------------------------------------------------------------------
Address 15: Airbags Labels: 1K0-909-605.lbl
Part No SW: 1K0 909 605 AB HW: 1K0 909 605 AB
Component: 6A AIRBAG VW8R 034 8000 
Revision: 05034000 Serial number: 003B6M03LPTY 
Coding: 0013889
Shop #: WSC 00066 000 00000
VCID: 6CF92CFC4FB98541A33-8039

Subsystem 1 - Part No: 1K0 959 339 F
Component: BF-Gewichtsens. 007 0005

Subsystem 2 - Serial number: 6332MSME16414570%

Subsystem 3 - Serial number: 6342MSME18275D68M

Subsystem 4 - Serial number: 6351HSME116F50476

Subsystem 5 - Serial number: 6361HSME112C140A%

Subsystem 6 - Serial number: 63727SME10600F2B 

Subsystem 7 - Serial number: 63827SME10600F6A%

No fault code found.

-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 1K0-953-549-MY8.lbl
Part No SW: 1K0 953 549 AP HW: 1K0 953 549 AP
Component: Lenksäulenmodul 036 0070 
Coding: 0000021
Shop #: WSC 00066 000 00000
VCID: 0021684C533171216FB-8055

1 Fault Found:
00883 - Ignition Switch (D) Terminal S 
012 - Electrical Fault in Circuit

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 1K0-920-xxx-17.lbl
Part No SW: 1K0 920 954 Q HW: 1K0 920 954 Q
Component: KOMBIINSTRUMENT 3HL 1212 
Revision: V0002000 Serial number: VWX7Z0GN24H099
Coding: 0023203
Shop #: WSC 00066 000 00000
VCID: 3A55DAA4756DEBF161F-806F

No fault code found.

-------------------------------------------------------------------------------
Address 19: CAN Gateway Labels: 1K0-907-530-V3.clb
Part No SW: 1K0 907 530 L HW: 1K0 907 951 
Component: J533 Gateway H07 0052 
Revision: H07 01 Serial number: 061007F1001795
Coding: E9807F070003021002
Shop #: WSC 00066 000 00000
VCID: 3041F88CA31121A1DFB-8065

No fault code found.

-------------------------------------------------------------------------------
Address 25: Immobilizer Labels: 1K0-920-xxx-25.clb
Part No SW: 1K0 920 954 Q HW: 1K0 920 954 Q
Component: IMMO 3HL 1212 
Revision: V0002000 Serial number: VWX7Z0GN24H099
Shop #: WSC 00000 000 00000
VCID: 3A55DAA4756DEBF161F-806F

No fault code found.

-------------------------------------------------------------------------------
Address 42: Door Elect, Driver Labels: 1K0-959-701-MIN3.lbl
Part No SW: 1K0 959 701 P HW: 1K0 959 793 L
Component: J386 TUER-SG FT 1133 
Revision: 32008001 Serial number: 00000009179101
Coding: 0001205
Shop #: WSC 00066 000 00000
VCID: 3B5BDFA07A57D2F97A9-806E

No fault code found.

-------------------------------------------------------------------------------
Address 44: Steering Assist Labels: 1Kx-909-14x-44.clb
Part No: 1K1 909 144 M
Component: EPS_ZFLS Kl.070 H08 1901 
Shop #: WSC 02069 000 90108
VCID: 354FC9985C7304898CD-8060

No fault code found.

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 1K0-959-433-MAX.clb
Part No SW: 1K0 959 433 CT HW: 1K0 959 433 CT
Component: KSG PQ35 RDK 052 0221 
Revision: 00052000 Serial number: 00000000000000
Coding: 13900F880186081B0904058FB0880F0488DCA0
Shop #: WSC 00066 123 12345
VCID: 0429645C47296D014B3-8051

Subsystem 1 - Component: Sounder n.mounted 

Subsystem 2 - Component: NGS n.mounted 

Subsystem 3 - Component: IRUE n.mounted 

No fault code found.

-------------------------------------------------------------------------------
Address 52: Door Elect, Pass. Labels: 1K0-959-702-MIN3.lbl
Part No SW: 1K0 959 702 P HW: 1K0 959 792 L
Component: J387 TUER-SG BT 1133 
Revision: 32008001 Serial number: 00000010079031
Coding: 0001204
Shop #: WSC 00066 000 00000
VCID: 3C59DCBC7F59D5C1733-8069

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 1K0-035-1xx-56.lbl
Part No SW: 1K0 035 180 L HW: 1K0 035 180 L
Component: Radio DE2 016 0020 
Revision: 00016000 Serial number: VWZ4Z7G2170231
Coding: 0040401
Shop #: WSC 00066 000 00000
VCID: 297715E880CB5069185-807C

No fault code found.

-------------------------------------------------------------------------------
Address 62: Door, Rear Left Labels: 1K0-959-703-GEN3.lbl
Part No SW: 1K0 959 703 Q HW: 1K0 959 795 J
Component: J388 TUER-SG HL 1120 
Revision: 12006001 Serial number: 00000002425828
Coding: 0001168
Shop #: WSC 00066 000 00000
VCID: 3E5DD6B46945C7D15D7-806B

No fault code found.

-------------------------------------------------------------------------------
Address 65: Tire Pressure Labels: 3C0-959-433-65.lbl
Part No SW: 1K0 959 433 CT HW: 1K0 959 433 CT
Component: RDK 0450 
Revision: 00052000 Serial number: 00000000000000
Coding: 0100101
Shop #: WSC 00066 000 00000
VCID: 0429645C47296D014B3-8051

No fault code found.

-------------------------------------------------------------------------------
Address 72: Door, Rear Right Labels: 1K0-959-704-GEN3.lbl
Part No SW: 1K0 959 704 Q HW: 1K0 959 794 J
Component: J389 TUER-SG HR 1120 
Revision: 12006001 Serial number: 00000002446815
Coding: 0001168
Shop #: WSC 00066 000 00000
VCID: 3FA3ABB06E4FCED9561-806A

No fault code found.

End-------------------------(Elapsed Time: 01:16)--------------------------

pay up.


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## stan067 (Feb 25, 2010)

Coolant temp sensor has two functions. 

One is to warn you of an overheating problem.

The second is to tell you the coolant level sensor in the coolant bottle is too low.

If the engine is hot and coolant light comes on you have to monitor the temp gauge or use VSCD to see the actual temp to see if it is actually overheating.

If the coolant light comes on when you know the engine is cold. (In the morning at start up.) You know its not overheating you just started it so it can't be hot.
On a cold start the coolant level is at it's lowest point. If this point is bellow the level sensor the light comes on and may flash on some models.
Once the light comes on cold for level too low it will stay on and not turn off. As the coolant heats up it expands raising the coolant level and the level sensor above the level that set the coolant light on.
The light doesn't go off once it is turned on for coolant too low even if the level rises it's designed that way. The low level coolant light will only go out if level rises enough to lift level sensor and you *cycle the key off and on again.* It will not turn off or reset until the key is cycled regardless or the level.

So basically I think your low on coolant.
Started on a cold start up the light comes on because the coolant level sensor is too low. You start and run the car for a few minutes the coolant heats up and expands rising the coolant level sensor to above the signal level. (About 1 inch) but the light is still on because you don't cycle the key. Try this start car drive a few blocks then cycle the key. If the light goes off you need to add coolant and you shouldn't see the light again on the next cold start. If after you top it off to the right level a week or a few days go by with out the light you have your answer.

If the light comes on again after a while then you have a small coolant leak. 

Longest explanation I ever saw to tell you your low on coolant:laugh:.

Good Luck


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## haskie (Mar 6, 2011)

stan067 said:


> Coolant temp sensor has two functions.
> 
> One is to warn you of an overheating problem.
> 
> ...


Thanks... yeah level is within the expected range...I was hoping Alexgc would pop in and tell us his final results, but sounds like a flush will fix it. Seems to only happen on cold mornings and yup, cycleing the ignition after she's warm makes it go away.

Thanks


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