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Discussion Starter · #1 ·
This is my daughters 2000 1.8t beetle which yesterday started acting up. First was the check engine light started flashing and then there was a shudder when accelerating. She quickly pulled over and shut the car off and called me. I hooked up the reader to it and came up with this list of error codes, 16795, 17704, 17763, 16684, 16685. Also the battery fuse box has a small amount of melting by the left most wire (passenger side).

So the first code 16795 is Secondary Air injection system: Incorrect Flow Detected. Not sure how this relates to the cars issues.

The second code 17704 is for error in mapped cooling system. Do I need to replace the temp sensor and/or thermostat?

Code 17763 is cyl. 1 Ignition Circuit: open circuit. Code 16684 random/multiple cylinder misfire detected and code 16685 is cal. 1 misfire detected.

So I would like to fix this myself but don't want to just start buying parts hoping I get the right one. Do I need a new battery fuse box and is this causing problems down the line? Or is it the coils, plugs? Or is it the icm or all of the above or something else. I would appreciate any help I can get.

Thanks,
Werner
 

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http://wiki.ross-tech.com/wiki/index.php/16795/P0411/001041

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

17763/P1355 - Ross-Tech Wiki

16684/P0300/000768 - Ross-Tech Wiki

16685/P0301/000769 - Ross-Tech Wiki

You have allot of classic issues; which can be researched in the above links. NOW, for the current drivability issues; I would say, that one of your coil packs has failed (in this case; cylinder #1). To confirm the failure; I would removed the #1 coil pack and put it in another cylinder (like #2) and see if the trouble code "travels" to the new location. If it does; like I suspect, then replace the coil pack. Get the correct high quality oem coil pack; from your local Volkswagen dealer and that way, you are assured to get a high quality part and get the latest revision. Avoid aftermarket low quality coils; that you get from your average auto parts store, as these will just prematurely fail and make your troubleshooting process harder to figure out and increase your brain damage! :) If you have the money and your coil packs DO NOT have the latest revision part number; you might consider replacing them all, as the older coil packs with earlier version part numbers are failure prone and might leave her stranded with more coil pack failures. If you're in there; you might pull the plugs, inspect them for wear and replace those as well. To find the correct plugs for your car; look up the correct NGK oe versions; by look them up here (be sure to use your correct engine code): http://www.ngksparkplugs.com/part_finder/index.asp Once, you get the misfire issues; handled, you can move on to the secondary air injection issues and either a bad thermostat or coolant temp sensor replacement, for the other trouble code.

Based upon the vw parts store; it seems you have the "bolt down" style (usually Hitachi as the oem) and these tend to be more reliable but more expensive. The current Volkswagen part number is: 06B905115E

http://parts.vw.com/parts/2000/Volk...artnumber=06B905115E&vehicleid=59368&siteid=9

Other vendors and other brands for the same part:

http://www.ecstuning.com/Search/06B905115E/

Do the coil pack swap testing procedure; replace the bad coils, plugs (if needed) and we will go from there.
 

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Discussion Starter · #3 ·
Thanks for the advise. I'm going to try the coil pack swap to see if I can isolate the issue and go from there.
 

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Discussion Starter · #4 ·
Did as you suggested and by swapping coil packs 1 and 2. The error moved with the swap so I have ordered a new coil OEM coil pack to replace the bad one. I'll deal with any other error codes after I have replaced the coil pack.

Thanks,
Werner
 

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Secondary air flow too low is almost always the corrugated hose from the air pump back to the Kombi/check valve. These crack on the 1.8t all the time.

The car likely needs a thermostat. DO NOT DRINK THE COOLANT SENSOR PUNCH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

If you have an OBDII tool that reads Live/Realtime data, these engines should run about 205F even below 70F outside ambient temperature.

Check the oil, if it is BLACK, change it now regardless of the mileage. The 1.8t oil pick up clogs up due to bad thermostats and contaminated oil.
 

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On that secondary air flow issue ...you might want to look at your air pump under the air intake. You should be able to see it fairly easy. Take a look at the seal and make sure that its not open. On mine, those rivet looking things that hold the 2 halves together gave and it was a little open. A little zip tie through the holes and everything was cool again.
 

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Discussion Starter · #8 ·
The part came in today and I replaced the coil pack today. The only error code left is the 16795 code which I will look into further. After driving it no lights on the dash came on however there is still a shudder in the engine when accelerating. Is this related to a missing cylinder or something else? Thanks for any help on this.
 

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http://wiki.ross-tech.com/wiki/index.php/16795/P0411/001041

The shuddering issue could be a number of things, would you describe it as missing, hesitation or?

Issues such as: low fuel pressure, ignition misfires, a faulty diverter valve, boost control valves, etc.; have all caused similar problems in my experience. There are many possible issues; it could be. A scan tool; that could read live data and fuel trims, could help determine what is going on.

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

You might try testing the fuel pressure, look at the fuel trim levels and test the diverter valve. Based upon your coolant temp sensor code; a bad cts or bad thermostat, can cause a rough idle, rich condition, stalling but this usually goes away, when the car warms up. Does the car run any different; cold vs. warmed up?


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Discussion Starter · #10 ·
So far I have only had it out for a 15 minute drive and there was no difference in the way if drove from the beginning of the drive to the end. The shudder feels like something is out of balance. When just cruising along without much throttle the shudder fades quite a bit but is still there.
 

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Well I would keep an eye out for new codes and try some testing, to see how thing are. Hopefully, you can find some clues; as to what the problem is. Keep us informed; as your testing and troubleshooting continues.


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It's been mentioned to check/change your spark plugs, I would definitely do this if you have never had them done while you have owned the car.
 

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check throttle body and #1 coil pack....

I've spent a zillion $$$ on my 1.8 GLX turbo... over nine months, I've earned a masters degree on "Hitler". Finally, after spending about $1,800. on repairs and parts, I got a $99. throttle body to replace a defective one, the #1 coil pack, and drove it on...

You must have the patience of Jobe to get through the trials on these vehicles. I love the car! They are crazy fun to drive!
 

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Discussion Starter · #14 ·
So the check engine light went back on today and after checking the error code is 17704 - Cooling system malfunction. Is this the temp cooling sensor or thermostat that is having the issue?
 

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According to the Ross Tech Wiki; it can be either. However, if you check the "special notes"; they say the freeze frame info, can give you an idea of which one it is:

17704/P1296/004758 - Ross-Tech Wiki

17704/P1296/004758
Contents [hide]
1 17704/P1296/004758 - Error in Mapped Cooling System
1.1 Possible Symptoms
1.2 Possible Causes
1.3 Possible Solutions
1.4 Special Notes
17704/P1296/004758 - Error in Mapped Cooling System
Possible Symptoms
Cold start issues

Possible Causes
Coolant Temperature Sensor (G62) faulty
Coolant Thermostat faulty

Possible Solutions
Check Coolant Temperature Sensor (G62)
Check Coolant Thermostat

Special Notes
Check the stored Freeze Frame data with this fault code. Freeze Frame information will be found in the fault code description (if the module supports it) or in Generic OBD-II if the vehicle complies with those regulations.
Freeze Frame data stored at -40 °C is generally an indication of a faulty ECT or wiring.
Freeze Frame data stored at +140 °C is generally an indication of a faulty ECT or wiring.
Freeze Frame data stored with in the 60-80 °C range is an indication that the vehicle was close to, but not within, the cooling systems normal operation range. The Thermostat itself or Cooling system components may be at fault.
 

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So the check engine light went back on today and after checking the error code is 17704 - Cooling system malfunction. Is this the temp cooling sensor or thermostat that is having the issue?
What I do not understand is why people do not monitor and benchmark specific values of their cars.

Engine temp should run about 205F and more often than not engines run too cold due to weak thermostats.

Just get yourself a smart phone OBDII App and interface and you can easily monitor on a real time basis as well as easily generate Log files.

Android - Touch Scan for $3.95 and ELM327 OBDII to Bluetooth interface.

iProduct - OBD Fusion for $9.95 and ELM327 OBDII to Wifi interface.
 

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Discussion Starter · #17 ·
Temp is running at 203-205 with AC off and 198 with AC on. I'm going to check that all vacuum tubes are good now. Any other suggestions would be great.
 

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Did you change; the thermostat or cts? When the A/C is on; it makes sense the temps go down, as the fans are on. It sounds; like your temps are normal. Are you getting any more trouble codes and how is the car running?
 

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Temp is running at 203-205 with AC off and 198 with AC on. I'm going to check that all vacuum tubes are good now. Any other suggestions would be great.
Thermostat is likely weak and needs replacement. TRUST me on this.

The ONLY reliable way to flag a weak/soft thermostat is when the ambient temperature is below 70F and you can get the car on a steady 40+ MPH cruise. Above 70F you can supercool the radiator with a garden hose and the engine should maintain at least 200F, but since you indicated the temp was dropping to 198F with the AC on, this tells me the stat is weak/soft.

This CAN AND WILL BE THE DEATH of the engine and cause the oil to sludge up and clog the oil pick up, all for a $10 part!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Change the thermostat, do it NOW before the Fall/Winter sets in and you find out the hard way. BTW, IF you are good, the stat can be changed WITHOUT removing the alternator. I have done it and a female member here did it after my suggestion.

http://newbeetle.org/forums/1-8-liter-turbo/58882-coolant-temp-sensor.html

http://newbeetle.org/forums/questio...-beetle/59077-malfunction-indicator-lamp.html

http://newbeetle.org/forums/1-8-liter-turbo/103113-overcooling-bad-thermostat.html

You can choose to listen to me and change the thermostat and O-ring seal for around $10 or screw around and replace the the coolant sensor and then you will be changing the thermostat during the Fall/Winter in the cold cussing the situation.

30%+ of most vehicles on the road have soft/weak thermostats. The proper engine coolant temperature is very important for the health and longevity of an engine. I am the original owner of a 1.8t NB Convertible that had a soft thermostat and only had 1 temperature related code that was pretty much dismissed as a coolant temperature sensor problem like ALL the others. I have had the clogged/restricted oil pick up and was close to loosing the engine.

I have learned more than I care to about this subject, REPLACE the thermostat and do it NOW!
 
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