www.tdiclub.com

Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You

Order your TDIClub merchandise and help support TDIClub


Go Back   TDIClub Forums > VW TDI Discussion Areas > TDI 101

TDI 101 Got a simple/basic TDI question? Are you a newbie (new to the forums). Feel free to post your question here.

Reply
 
Thread Tools
Old October 5th, 2019, 16:57   #1
erasedhammer
Newbie
 
Join Date: Sep 2019
Location: Maryland
TDI(s): 1996 Passat
Default Temp gauge dead, but vagcom picks up coolant temp

1996 Passat TDI.

Temperature gauge in gauge cluster always shows nothing, seems completely dead.
Hooked up my vagcom scanner and it can read the coolant temperature just fine.

Does this mean that the gauge is the problem and not the actual sensor?
erasedhammer is offline   Reply With Quote
Old October 5th, 2019, 17:21   #2
Nuje
Veteran Member
 
Join Date: Feb 2005
Location: Island near Vancouver
Default

I don't know about the Passat, but there are four pins on the Mk4 G/J/B cars. I don't know the pin-out, but I'd guess that one goes to the gauge, one to the computer, one for ground and one for...good luck(?).

Who knows. But I've seen something similar on one of my G/J/B cars, and sure enough, replacing the coolant temp sensor made everything work properly again.

Again - I may be way off base, but that's my $.02. Open to correction.
__________________

His ride: 2015 GSW SEL TDI with MIB2, Active Info Display, DSG tune
Her ride: 2016 A3 e-tron

His other ride: 2015 Giant Propel SL Di2
Nuje is online now   Reply With Quote
Old October 5th, 2019, 19:18   #3
Mongler98
Veteran Member
 
Join Date: Mar 2011
Location: Northern MD
Fuel Economy: Race: 12mpg, Gandma:65mpg
Default

not uncommon for the cluster to have issues, i would not be surprised if the wiring harness behind the dash is damaged or that the PCB has started to delaminate the solder points. easy way to find out, pull the cluster out, its very easy to do, test the wires coming into it for the cluster and inspect the cluster and or test it, not sure what the volts and ohms range is supposed to be for the coolant gauge but im sure someone else can chime in.
I would just get a scangaugeII and put it some place easy to see without taking your eyes to far from the view ahead. the temp gauge was and is fairly uselss as it has a wide range that just shoes strait up normal temp reading. you can start to overheat the engine and the gauge will still say its ok. worthless POS vw garbage.
Mongler98 is offline   Reply With Quote
Old October 5th, 2019, 20:28   #4
erasedhammer
Newbie
 
Join Date: Sep 2019
Location: Maryland
TDI(s): 1996 Passat
Default

Quote:
Originally Posted by Mongler98 View Post
not uncommon for the cluster to have issues, i would not be surprised if the wiring harness behind the dash is damaged or that the PCB has started to delaminate the solder points. easy way to find out, pull the cluster out, its very easy to do, test the wires coming into it for the cluster and inspect the cluster and or test it, not sure what the volts and ohms range is supposed to be for the coolant gauge but im sure someone else can chime in.
I would just get a scangaugeII and put it some place easy to see without taking your eyes to far from the view ahead. the temp gauge was and is fairly uselss as it has a wide range that just shoes strait up normal temp reading. you can start to overheat the engine and the gauge will still say its ok. worthless POS vw garbage.
Yeah I wouldn't mind it, only the coolant light is flashing at me. I figured they are connected problems... maybe just low coolant.
erasedhammer is offline   Reply With Quote
Old October 6th, 2019, 08:44   #5
JETaah
 
Join Date: Jan 2001
Location: mi 48836
Fuel Economy: 53 max, 42 min, average 46
Default

Quote:
Originally Posted by erasedhammer View Post
Yeah I wouldn't mind it, only the coolant light is flashing at me. I figured they are connected problems... maybe just low coolant.

Could be that the reservoir's probes for the coolant level are coated with funk and giving a false reading if your coolant level appears to be right. On A4 cars they are exposed where you can run a brush across them to clean them. Don't think that they are accessible on the Passat's reservoir.
If that is the case then a replacement reservoir is not that expensive.
https://www.idparts.com/coolant-expa...b4-p-1157.html
But do a continuity check on the harness leads to the ECU or cluster...don't remember if they go straight to the cluster or not.
Do you have any signs of contamination (bathtub ring) in the reservoir?
__________________
1999.5 a4 Jetta, port matched, RC2, sprint 520's, 1.5" lift kit
1996 Passat B4V, coat hanger supported exhaust system,
Visit me www.martinbergelllc.com

Last edited by JETaah; October 6th, 2019 at 08:49.
JETaah is offline   Reply With Quote
Old October 7th, 2019, 11:06   #6
erasedhammer
Newbie
 
Join Date: Sep 2019
Location: Maryland
TDI(s): 1996 Passat
Default

Quote:
Originally Posted by JETaah View Post
Could be that the reservoir's probes for the coolant level are coated with funk and giving a false reading if your coolant level appears to be right. On A4 cars they are exposed where you can run a brush across them to clean them. Don't think that they are accessible on the Passat's reservoir.
If that is the case then a replacement reservoir is not that expensive.
https://www.idparts.com/coolant-expa...b4-p-1157.html
But do a continuity check on the harness leads to the ECU or cluster...don't remember if they go straight to the cluster or not.
Do you have any signs of contamination (bathtub ring) in the reservoir?
I think it's just dirty on the outside.
I'll check it today, but I don't recall seeing any fluid in there....
Engine still stays at temperature, IR temp monitoring, so I never bothered to check the coolant level
erasedhammer is offline   Reply With Quote
Old October 7th, 2019, 11:15   #7
oilhammer
Certified Volkswagen Nut Vendor
 
oilhammer's Avatar
 
Join Date: Dec 2001
Location: St Louis
Fuel Economy: fantastic
Default

Quote:
Originally Posted by erasedhammer View Post
1996 Passat TDI.
Temperature gauge in gauge cluster always shows nothing, seems completely dead.
Hooked up my vagcom scanner and it can read the coolant temperature just fine.
Does this mean that the gauge is the problem and not the actual sensor?

The scan tool data comes from the Engine controller side of the CTS, not the gauge side. And on that car, the Instruments work a little differently than the newer cars.

The sensor for the older cars used to be 357-919-501-A but got superceded to 6U0-919-501-B some time in the last decade. I would try that first, cheap and easy.
__________________
oilhammer
www.cardocautomotive.com
oilhammer is offline   Reply With Quote
Old October 7th, 2019, 18:26   #8
AndyBees
Veteran Member
 
AndyBees's Avatar
 
Join Date: May 2003
Location: Southeast Kentucky
Default

Temp sensor is the problem .. follow Oilhammer's advice.

The same issue is going on with my 03 TDI Jetta, the gauge is on zero. I plan to change it when I do the TB job. I've seen this numerous times.
__________________
This is the TDI Club, a place to share experiences & ideas, ask for help, etc. Welcome Newbies! Sarcastic and condescending posts shouldn't be welcome.
AndyBees is offline   Reply With Quote
Old October 7th, 2019, 19:11   #9
Mongler98
Veteran Member
 
Join Date: Mar 2011
Location: Northern MD
Fuel Economy: Race: 12mpg, Gandma:65mpg
Default

Quote:
Originally Posted by oilhammer View Post
The scan tool data comes from the Engine controller side of the CTS, not the gauge side. And on that car, the Instruments work a little differently than the newer cars.
The sensor for the older cars used to be 357-919-501-A but got superceded to 6U0-919-501-B some time in the last decade. I would try that first, cheap and easy.
so why then does my 98 jetta have a 0 reading on the scangauge when i disconnected the temp sensor on the upper hose? i thought the b4 and the jetta both had nearly the same engine?
Mongler98 is offline   Reply With Quote
Old October 8th, 2019, 04:53   #10
oilhammer
Certified Volkswagen Nut Vendor
 
oilhammer's Avatar
 
Join Date: Dec 2001
Location: St Louis
Fuel Economy: fantastic
Default

That is not the sensor we are discussing. That is for the A/C and A/C alone. Has zero to do with the Engine controller, or the gauge in the Instruments.
__________________
oilhammer
www.cardocautomotive.com
oilhammer is offline   Reply With Quote
Old October 8th, 2019, 06:15   #11
Mongler98
Veteran Member
 
Join Date: Mar 2011
Location: Northern MD
Fuel Economy: Race: 12mpg, Gandma:65mpg
Default

Sorry, not on the hose. On the plastic tee on the head to the radiator hose. Sorry I was not specific
Mongler98 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Coolant temp gauge Cha2ga VW MKIV-A4 TDIs (VE and PD) 3 April 29th, 2015 06:41
Replaced the coolant temp sensor. fixed short GP cycle, now temp gauge is wrong. 2TDIguy VW MKIII-A3/B4 TDIs 3 October 21st, 2010 18:55
coolant temp gauge prob johnjames1234 TDI 101 13 February 18th, 2010 15:38
Coolant Temp Gauge SheeB Ontario 4 February 9th, 2009 17:30
Fuel temp, charge air temp, coolant temp??? Turbosprezarka TDI 101 3 December 5th, 2006 17:03


All times are GMT -7. The time now is 20:20.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
1996 - 2017, All Rights Reserved
Page generated in 0.15942 seconds with 13 queries
[Output: 106.47 Kb. compressed to 90.60 Kb. by saving 15.87 Kb. (14.91%)]