# 02 New beetle o2 sensor bank 1 sensor 1 no activity. cooling system failure



## Tedrow1 (Sep 28, 2018)

Hello. I have a new to me 02 beetle 1.8t that is throwing an 02 sensor bank 1 sensor 1 no activity code. I have replaced the sensor with a new Bosch 17351. I have tried checking the voltage to the sensor but am only getting 5 volts on 2 of the pins. Any help? I am also getting a cooling system failure p1269 code. It has antifreeze and i just replaced the sensor on it too.


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## billymade (Jan 29, 2008)

Hey, please post; all the codes you are getting and not just the descriptions. As to the 02 sensor problems; I would run the factory service manual tests, to test the sensor, plus the ecu/wiring and if it isn't working right, then the ecu maybe damaged/bad. Another problem, that I had; was a 02 sensor trouble code, that kept coming back, even though I replaced it! This got me REALLY confused; so, after a test drive, the code came back, after I cleared it and so, I decided, to do a "hard reset" of the ecu. I did the hard reset and the code went way, stayed away! So, you might give that a shot; it worked for me. A hard reset, it accomplished; by removing the pos/negative battery cables, touch them together for a number of seconds and then, reinstall, back on the battery. This wipes out, the settings in the ecu and it may, help, this is kind of like "rebooting" a personal computer, when it is not working right. 

As for the cooling code; the thermostat or the waterpump, can/could be bad. As to the trouble code you posted; I wonder, if you could double check it and wonder, which scan tool, you are using? This code, seems to be Diesel related: 

http://wiki.ross-tech.com/wiki/index.php/17677/P1269/004713

Try some testing and doing the hard reset; post up all your codes, then we can go from there! Thanks!


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## Tedrow1 (Sep 28, 2018)

I am getting p0134 for the 02 sensor. it says p1269 cooling system failure. It seems only occur when the engine is cold. IE first thing in the morning.
I have read of the thermo sticking open and am going to replace it. I have also read that they open at 190 but was told by a mechanic that it should be 210

I am using a centech scanner. 

This morning I monitored the ECT and it took around 30 minutes for it to reach 180 degrees. IAT was 102.2. I also saw the longft% was -24 to -25 
shrtft was 0.8%, the shrtftb1s2 was at 99.2%. I also noticed the fuelsys1 flipped from cl to cl error. I am not an auto mechanic by any means so I don't know if this will help anyone.


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## billymade (Jan 29, 2008)

https://www.engine-codes.com/p0134_volkswagen.html

Here is the service manual; testing for the oxygen sensor/wiring/ecu; confirm, before replacing the sensor. If you buy a new 02 sensor, then be sure to buy a oem high quality Bosch sensor. 

https://workshop-manuals.com/volksw...__o2_sensor_regulation_after_converter_check/

Be sure to keep advancing the pages; until you get to the correct sensor and the "aftermarket scan tool" area, to do testing without a VW specific scanner. 

https://www.google.com/search?ei=VU.....0....1..gws-wiz.......0i8i13i30.Pb9m9jJu-_M

Again, the trouble code; is injector related but maybe, your centech is giving you the wrong trouble code. The Harbor Freight tools are cheap but many of the Chinese scan tools, will give you incorrect trouble codes or definitions of the code itself. 

Based upon, how long, it took to get up to 180F; I would guess, that the thermostat is stuck open. 

This is the typical trouble code given; for the cooling system issues: 

http://wiki.ross-tech.com/wiki/index.php/18613/P2181/008577

Note: at the end of the page; Ross Tech, explains, how to pinpoint the problem, by looking at the pending codes and when the temps throw a code, which part is culprit (thermostat, sensor, waterpump, etc.). 

Your fuel trims, are pegged and certainly, not in the normal range (+ or - 10%). Read more about this here: 

http://wiki.ross-tech.com/wiki/index.php/Fuel_Trim_Info

The low temps and the 02 sensor; not working correctly, could impact your fuel trim readings. Do some work, testing and repairs, then get back to us and we can go from there! Thanks!


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## Tedrow1 (Sep 28, 2018)

Thank you I will investigate it further this weekend


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## Tedrow1 (Sep 28, 2018)

Ok. It poured down rain last night. I started the bug up this morning and it idled rough. Put it in reverse and it barely wants to move. I put it in drive and same thing. I turned it on and off a few times but it still didn't want to react to the throttle. I revved the engine for a few minutes and it starts to act normal. I put it in gear and all the sudden it decided to move. About 10 minutes down the road the blue cooling light went out and the CEL came on. When I got to work I checked the codes and its the p1269 cooling system malfunction. Looked at all the numbers and the fuel trims were normal. I monitored it on the way home and the car is running good. shrt fuel trim was at 14 long was -0. I don't have an android device for the Vag testing that is highly recommended by everyone. Is there any other tester recommendations?


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## billymade (Jan 29, 2008)

I still wonder, if the scan tool codes; are questionable, at this point but your code, seems to be related to injector #4, I have a feeling, your code description maybe wrong or the code itself is wrong (both common on the cheaper chinese scan tools). 

https://www.engine-codes.com/p1269.html

For a VW specific scan tool, much depends on your budget and how easy you want to use it, would be (handheld, used with your portable device like your phone or connected to a window pc). 

There are many, cheaper handheld scan tools, like the Chinese knocks "VAG" tools on amazon (the VAG 401; is a example, does live data/coding/output testing/throttle body alignment, etc) those go as cheap as $20 up to $200, then there is OBDEleven, which is a good modern software app based solution, that uses a Android phone, has a wireless bluetooth dongle, that plugs into the OBD II port ($50-$80 for basic app access or more for the "pro" version) and finally VCDS by Ross Tech, the industry standard, in independent shops that specialize in VW repairs, it is basically a "clone" of the VW factory 1552 scan tool, that the VW dealerships use ($200 for enthusiast/home user limited VIN #'s). 

So, it depends on your budget; whether you want to use a separate hand held device (like your centech), you want to use a Android device or are willing to use a windows based pc or device, like a tablet. 

Discuss your budget and what device/portability options you like and we can go from there.


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## Tedrow1 (Sep 28, 2018)

I bought this bug for my daughters 16th. I don't typically deal with car repairs when it comes to being in depth, I have a friend that is into that stuff,. He hates VW's though. I do like the hand held scanner for its ease of use. 
I'm not really tech savvy to be going and using bluetooth and buying android computers. This computer is 12 yrs old and running XP! As for budget $150 would be about all I would spend on a scan tool.
Do you recommend taking it to a dealer to verify the code? I've read on other forums people having the same code and description 
on Passats and beetles with the 1.8t. Will seafoam clean the injector? 
Another weird thing that happens is it sounds like an actuator is activating from the trunk of the car when I hit the brakes. It sounds like its somewhere near the evap system near the tail light. It sounds exactly like the trunk and the fuel door actuators when activated.


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## billymade (Jan 29, 2008)

Yeah, it is hard to know for sure; if you trouble code is the right one with the centech scanner, it is questionable. Most auto parts stores, will scan your car for free and that way you could verify the code (they typically; offer a scan tool for rent as well). 

As for your VW/VAG scan tool and your budget of $150; it depends on how much capability you want and the better scanners, are easier to use. Based upon what you are saying; it seems you are ruling out obdeleven and VCDS. That leaves you with the less expensive "VAG" tools; that are sold on Amazon, there are many different models and the higher the price, have better support and ease of use. 

I strongly, recommend; you purchase the tool from Amazon, that way, you can check it out and send it back without return hassles, if it is defective or you end up, not liking the tool or it is just something you don't find easy or good to use. 

The VAG 401, has been; a affordable version, many have bought, it is a Chinese knockoff, is kinda clunky to use and limited support, from the manufacturer. It can do alot of things but it takes some getting used to, to use it but it is a good price @ $50-$60. 

https://www.amazon.com/XTOOL-VAG401-Scanner-Actuation-Function/dp/B013LPC40E

Here is a basic "overview", of what it is like to use the tool and the basic functions, you would use and things you can do with it. 

https://www.amazon.com/XTOOL-VAG401-Scanner-Actuation-Function/dp/B013LPC40E

Aside from that, there are so many "VAG" scan tools; I cannot really go through them all. One company, called FOXWELL; seems to make some scan tools, that seem a bit better and they have support out of Australia. The FOXWELL is also sold under; the "Schwaben" brand, from ECSTUNING, so that might be good. 

So, their scan tool; specifically for VW/AUDI would be the VAG Scanner NT500. This tool, is hitting your budget price @ $150. If you have other cars, you might check the NT510; which you can upgrade the software to, to add other makes/models to increase compatibility of the tool. 

http://www.foxwelltech.com/product/item-125.html

There, are many others but I just cannot go through them all. The key is to get a scan tool that can: 

1. support live data
2. has VW/AUDI full compatibility
3. can do coding/programming
4. can do output testing 
5. can do things such as throttle body alignment, etc. 

So, I hope this helps; if you have anymore questions, let me know! 

PS: I use VCDS by Ross Tech and have since 2007; it is a great tool with excellent support from a USA based company, you can call on the phone with American support staff and it comes with lifetime free software upgrades. It is a great tool but it does require; a windows based pc or tablet. 

More info here: https://www.google.com/search?q=vcd...rome..69i57.6359j0j7&sourceid=chrome&ie=UTF-8


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## Rockerchick (May 10, 2005)

Don't forget about local enthusiasts! Many own VCDS and will lend a hand. Facebook is a good place to find local help. There is also a locator map for those who own the tool: https://forums.vwvortex.com/showthr...wners-pm-me-your-info-requested-in-the-thread

There is also the option of a local independent VW shop if you are in a bind with reading codes.


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## Tedrow1 (Sep 28, 2018)

I think I have solved the o2 sensor issue. I did some checking and replaced the MAF and have not had an o2 code since. fuel trims are down to around -3. I was wrong on the other code it was 1296 and not 1269. (old age setting in) 

I replaced the thermostat and ran it several miles while watching the ECT on the test set. it reached 204.8 at the maximum and stayed right at 203. The heater was blowing hot air. When I got back I checked the hose coming from the thermostat and it was cold.

The thermostat is an aftermarket (#14419 carquest) from advanced auto. According to the spec on their site it says opens at 190. Has anyone had an issue with aftermarkets not working? 

I had a 90 Mazda b2600 and the thermostat would go out almost every winter no heat. I found that unless it was a Mazda thermo it wouldn't work right to put out heat.

I'm going to stop by the VW dealer and pick one up. Any suggestions about flushing the system or just try a vw thermostat?


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## billymade (Jan 29, 2008)

OK! Finally! As I suspected, the trouble codes; was wrong and now it makes sense!  :banghead:

http://wiki.ross-tech.com/wiki/index.php/17704/P1296/004758

Read the above definition; they narrow it down, to either the thermostat or the coolant temp sensor. BOTH are common failure points, NOTE: that they show, by looking at the obd II "freeze frame" info, it can narrow down the culprit!  The ecu senses, that the sensor is bad/wrong or the thermostat is taking too long to open up. 

Check out these videos; for more in depth info about these two failure prone parts: 

https://www.youtube.com/watch?v=TwQ-2xp_TK4

(this is for a different era engine but the principles and trouble code are the same): 

https://www.youtube.com/watch?v=-_inruGy8kE

As noted, both of the parts; have a history of failure. It is a good idea, to replace them with a high quality oem part. Based upon online research; I believe, people have come to the conclusion, that the German company Behr, makes the thermostats for VW. 

Also, what you are in there; it could be a good time to replace the plastic coolant flange, for the thermostat. They are selling aluminum upgraded ones for cheap and that is a nice upgrade, as the plastic ones, degrade over time, get mushy, cracked and always ends up leaking at some point. :facepalm: A number of companies, are selling these metal upgraded cooling system parts and they are affordable. 

thermostat housing/flange: VW part # 06A121121C

https://www.google.com/search?q=Cas...=chrome..69i57j69i60&sourceid=chrome&ie=UTF-8

Most are selling, for about $40; this guy, is $20 with free shipping and comes with the needed oem o-ring: 

https://www.ebay.com/itm/WhanAB-Cas...h=item3d38505364:g:fvsAAOSw0odbvVq-:rk:7:pf:0

Lastly, if you decide to replace the coolant temp sensor; be SURE, to inspect the plug and terminal ends, going to the sensor. These plugs/terminals, have also, be known; to crack and have connection issues, over the years. So, if they are damaged, you can get new plugs/pigal assembly or buy the parts individually; from your local vw dealer. 

There have been a couple of different types of sensor and plugs/amount of pins for them, over the years. Here are the most common types: (you can look at the part #'s on the old part or your local VW can get your the right parts, based upon your VIN #): 

VW part # 059919501A (4 pin)

HOUSING VW # 4B0973712 (4 pin)

https://www.google.com/search?q=vw+...ome..69i57.10704j0j7&sourceid=chrome&ie=UTF-8


Hope this helps and you finally; get this trouble code handled and your car, FINALLY, runs right and the temps are @ the level they should be! WHEW! :wave:eace:


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## Tedrow1 (Sep 28, 2018)

I suspect I got a thermostat that will not open since the hose from the thermostat housing to the radiator never got even warm after running for 20 minutes and the ECT reaching 204. I am going to try a different one. I also noticed neither cooling fan ran when it got hot. I will troubleshoot it in the morning.
As for the aluminum housing the fine print on the ebay link says that it will not fit ANY New Beetle. I have seen them on other sites and will get one.
I've already replaced the temp coolant sensor and it works. That was what all the blogs were saying is the most likely issue but with my luck it could be low washer fluid turning on the cooling system light. I've come to believe if its a common failure part that mine is ok and its gotta be something ridiculous causing my issues. 
Thanks for the insight and advice. Ill press on until figure this thing out and let you know what i find.


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## billymade (Jan 29, 2008)

Diagnosing the cooling system, can be confusing; the lack of a temperature gauge and the idiot light itself, can be misinterpreted.

Here are the coolant light modes: 
Blue coolant light = engine cold Flashing blue coolant light = fault in the coolant monitoring system Flashing red coolant light = low on coolant Steady red coolant light = engine overheating, pull over and stop engine IMMEDIATELY and do not run until the problem has been identified.

For the thermostat, many times; there is air in the block and the temps can get high/the car overheated. Some deal with this with the use of a coolant vacuum filler tool; others have drilled a small hole in the thermostat or used other techniques, to burp the system.

This is discussed in this video @ 6:00:

https://youtu.be/6Hb_zuttLqE

As for figuring out your problem; did you note the freeze frame data shown in your scan tool for the trouble code? This can pinpoint the reason, the code is being thrown. This is discussed in the ross tech trouble code definition page here:


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## billymade (Jan 29, 2008)

Look at the “special notes” section here: 

http://wiki.ross-tech.com/wiki/index.php/17704/P1296/004758

As for the aluminum thermostat housing/flange; they are all the same fitment/part for the 1.8T and 2.0L engines.


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## Jonathan41 (5 mo ago)

I am an original owner of a 2004 NB with 1.8T engine. When you get O2 sensor low codes, DOUBLE CHECK your fuse panel for a blown fuse or fuses. I use the fuse diagram in the Bentley manual to start. I also found that you may need to visually check all fuses because sometimes the fuse code in the Bentley manual is not 100% inclusive. For example, I got a code for low circuit O2 sensor (code) P0031. Upon investigation, it was a blown fuse position 43 (10A fuse) described on the fuse chart as "Engine Control". Good luck!


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## billymade (Jan 29, 2008)

Any updates? 


Sent from my iPhone using Tapatalk


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