Bora 1.6 16V (BCB) EMISSIONS WORKSHOP

[vkeza057]

Hi guys,
Here is my problem:
I just bought a 2002 Bora 1.6 16V 77kw (BCB). Car runs great and the engine is very quiet. Just before my first trip I put some fuel in the tank. I'm not sure about the quality of the fuel. The trip was mainly uphill. It was raining. The CEL lit and EMISSIONS WORKSHOP was on the display. The next day I read the forums and found that overfilled (oil) engines do this. Checked the oil level... almost 0.5 liters overfilled. Removed the extra oil... no change.
Next step was VAGCOM:

P1426 35-00 EVAP Purge Valve N80 Open Circuit
P1116 35-00 O2 Sensor Heating B1 S1 Open Circuit
P1118 35-00 O2 Sensor Heating B1 S2 Open Circuit
P1105 35-00 O2 Sensor Heating B1 S2 Heating Circuit Short to Plus
P1196 35-00 O2 Sensor Heater Circuit B1 S1 Electrical Malfunction
P1180 35-10 Linear O2 Sensor/ Pump Current Short to Plus

The car has no problems apart from the mentioned codes and messages. Could the bad fuel or overfilling or rain(!?) damage the sensors? My guess is it's the pre-cat O2 sensor. Need help.

I put my question here after reading all the EMISSIONS WORKSHOP threads around. All of those seem to have one thing common: the VR6 or 1.8T engine. My engine is a 1.6 16V BCB. Also, the trouble codes are almost always different.

Problem:
CEL and EMISSIONS WORKSHOP lit (see a list of trouble codes in the first post)

Possible causes:
- Engine slightly overfilled with oil + uphill driving
- Low quality fuel put in the tank just before the (uphill) trip
- My engine temp. sensor was faulty. Engine would cool down a little bit when driving fast(er). Replaced. Temp is fine now.
- Rain

Theories:
- Oil clogged the pre-CAT (B1 S1) O2 Sensor? This is my best guess so far. Could this be the cause for the EVAP and other codes?
- Oil clogged the O2 Sensors and/or CAT? Shouldn't I be having trouble driving if this was the case? Also, shouldn't there be P0420 code (Catalyst System Efficiency Below Threshold)?
- Low quality fuel messed my valves. I read this in this forum.
- Low engine temp. caused the CAT to fail? I read this somewhere in the forum. Not likely, I guess.
- Connectors got wet becauuse of the rain. I don't think this is likely.

Additional info:
When I reset the codes, they come back in a few seconds. I think I saw the O2 error coming back first. Not sure.

Hope someone had a similar problem and has a quick, simple and cheap solution!

[mikeybutch]

How much had you driven before this trip and these probs?I have no expertise in these matters but I know overfilling is risky.This does not seem a lot of oil to cause such grief and I confess that I overfilled my V5 by about this much last time I changed the oil and I drove a few miles before checking and taking some out.Hope you get some more helpful answers

[towcestervag]

if you have a vagcom then go to advanced measuring blocks
check the lambda operation and heater operation
go to output test to check the acf valve is working

[vkeza057]

First of all, thank you guys for helping!

I checked the measuring blocks, but only briefly (my focus was on the EVAP). I'll try the advanced measuring blocks in a few days to check the lambda and heater operation. Thanks for the tip!

UPDATE:
Went to my mechanic today. We solved all DTCs except the last one. Here's what we did:

P1426 35-00 EVAP Purge Valve N80 Open Circuit
Cleaned the EVAP Valve and Container and replaced the fuse (marked with engine pic on the reference card). After checking it works (output tests), we cleared DTCs and I had 15 min of happy motoring until the next EMMISSIONS WORKSHOP message. Only one DTC this time (read on).

P1116 35-00 O2 Sensor Heating B1 S1 Open Circuit
P1118 35-00 O2 Sensor Heating B1 S2 Open Circuit
P1105 35-00 O2 Sensor Heating B1 S2 Heating Circuit Short to Plus
P1196 35-00 O2 Sensor Heater Circuit B1 S1 Electrical Malfunction
All gone after fuse change.

P1180 35-10 Linear O2 Sensor/ Pump Current Short to Plus
Still here. Intermittent. Linear O2 sensor DTC is also known as Reference voltage DTC. It's the 1V that ECU generates to compare it to 0.2-0.8V that O2 Sensor measures based on O2 in the exhaust. (Please correct me if I'm wrong... I often am. :) )

The car still runs great. The same EMISSIONS WORKSHOP is still there, but sometimes it takes some time to display and cause CEL to light up.

What could be causing this? Could it just be bad wiring?

[vkeza057]

This morning I did a DTC scan with my old VAGCOM. Well, the P1180 was still there. This time it said 35-00. Also there was a P1116 again. This DTC was marked as intermittent this time. :)
Cleared them and none returned. I guess they'll (or at least P1180) be back soon.

I think it might be the O2 after all since the car was running at working temperature at the time of the scan so the heating circuit was not used so it didn't throw any errors. Let me explain. Yesterday we cleared the codes and took the car for a drive. It took 15 minutes for it to throw the DTC. Later that day and this morning when the engine was cold it threw the DTC almost immediately.

My main concern now is the P1180. I'm thinking about replacing the very expensive pre-CAT 5-wire O2 sensor but I'm concerned that the P1180 will still be there making the purchase pointless as the car is running great regardless and I'd still be having the CEL.

UPDATE:
I drove the car for a few minutes and the DTC returned as expected. Also, it was only the P1180 as expected.

ANOTHER UPDATE:
Maybe my cold/hot engine theory is faulty. The car will show the EMISSIONS WORKSHOP message immediately only when the CEL is already lit.

[vkeza057]

JET ANOTHER UPDATE:

As of this evening all the codes are back. The only difference is I filled the tank with 100 octane unleaded fuel. Also, after some investigating I found these comments:

"Fit a new sensor (the one before the cat) and hope it is not a wiring fault or check all the wiring from the sensor first. If the wiring breaks anywhere, it is usually between the box mounting and the fixed point under the batttery tray."

"vw golf 1.6 16v azd engine (same line as bcb) p1180 code and mil light on. have put new lambda sensor bank 1 on have checked all wiring to sensor and the b+ wire all ok cleaned all earths run out off ideas"

"vw golf 1.6 16v 53 reg eng code azd, engine management light has come on again, i have had both oxy sensor replaced and the cat"

Guess it's time to check the cables thoroughly and hope I find a section that has breaks, burns or crushed parts!

What I really need right now is someone with a 1.6 16v 77kW (AUS/AZD/ATN/BCB) engine that had problems like these and found a solution or someone with a shop that had first hand experience with this. You wouldn't believe how many questions are out there regarding problems similar to mine with no answers! Even if they seem to be on to something, the thread just dies. I guess people just stop writing after they make their problem go away. Come on guys, share! :)

[vkeza057]

Ok. Problem solved!
Turns out the heat shield covering the pre-cat O2 sensor burned the wires.
All of the insulation was gone causing the 5 O2 sensor wires to touch and create all sorts of errors. Also the 10A fuse 43 (O2 sensors, EVAP purge valve...) was always burnt, sometimes instantly, sometimes in 15 minutes.

After some soldering and insulating the problem is gone.

If you encounter a similar problem, do a DTC scan and disconnect everything mentioned in the scan. Check fuse 43 and replace if burnt. Drive the car for a little while then check the fuse 43 again. If it’s ok your wiring is fine. Next step: Reconnect the valves and sensors one by one with a short test drive in between. The fuse will blow sooner or later. Check the cables of the sensor or whatever it is that burned the fuse. Be persistent and thorough. You'll find it.

Hope this helps someone. :)

[mikeybutch]

Good news thanks for the tip and many happy miles

[LDVincenzo]

Hi guys,
Im getting the same issue but I have replaced my lambda sensor and still got emissions workshop light. I'm also getting I take temperature signal too high, VCDS is reading -40 but I just replaced the MAP sensor as I understand they are both integrated and I still get an issue. No crushed wires under battery, fuse 43 all OK, only thing I ha wnt checked is the post cat sensor, perhaps my cat is on its way out but would I not get a DTC telling me that?

Many thanks
Luke

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[LDVincenzo]

No more emissions workshop light! After a more thorough search I found the broken wire and another that was close to going! https://uploads.tapatalk-cdn.com/20190601/36edb959fc9d358b74e510d58d369a44.jpghttps://uploads.tapatalk-cdn.com/20190601/a6d71aed531fc6d8c91a857539cf7d50.jpghttps://uploads.tapatalk-cdn.com/20190601/3518f4e155fbbc461c3077bbbd33507a.jpghttps://uploads.tapatalk-cdn.com/20190601/e439b391b3ae061f9fde84a5b8d03a3f.jpg

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