Help with VAG COM tests

[achb5]

Trying to diagnose my ECL light in my 2001 b5
Rear O2 coded out, both Fronts are New universal Bosch.
New Epic Tuning Tune

Im very new to VAGCOM

How does one use Vag-com to test the harness up to where the sensors connect? Wiring harness passes my visual inspection, no flaws in wiring externally.
How can I use Vag-com to test MAF, FPR, and the o2s.

Im having a hard time finding what blocks to measure and what values to expect for normal opperation.

These are the codes I pulled.

17524 - Oxygen (Lambda) Sensor Heating; B1 S1
P1116 - 35-00 - Open Circuit
16518 - Oxygen (Lambda) Sensor B1 S1
P0134 - 35-00 - No Activity
16534 - Oxygen (Lambda) Sensor B2 S1
P0150 - 35-10 - Malfunction in Circuit - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 -
16688 - Cylinder 4
P0304 - 35-00 - Misfire Detected
16687 - Cylinder 3
P0303 - 35-00 - Misfire Detected
16689 - Cylinder 5
P0305 - 35-00 - Misfire Detected
16839 - EVAP System
P0455 - 35-00 - Large Leak Detected
17964 - Charge Pressure Control
P1556 - 35-00 - Negative Deviation

Readiness: 0110 0100

Thanks in advance

[JnormS4]

Do you have android?

[getslideways]

Are all of these recent codes? Or when was the last time you cleared them.

[zillarob]

That doesnt look like it is going to be fun.
Other than the codes, vagcom isnt really the right tool for testing the things you want to test.
Psi test, voltmeter, and wiring diags are prob what you are looking for.

[JnormS4]

He needs to save, clear then see what comes back.

[achb5]

Do you have android?

I dont

Are all of these recent codes? Or when was the last time you cleared them.

All recent codes. Its a new engine build. The 10 days ago i pulled up these o2 codes plus one for the Drivers EGT, -> replaced both o2 and pcb boards in the egts over the weekend. -> pulled these codes this morning. Egt's seem to be fixed :)

That doesnt look like it is going to be fun.
Other than the codes, vagcom isnt really the right tool for testing the things you want to test.
Psi test, voltmeter, and wiring diags are prob what you are looking for.

OK, sounds good. Did a pressure test today -> nothing major, buttoned up a few hatches.
Thoughts on how to proceed with my multimeter? I think I should see somewhere between 0 and 1 V across the power for the o2 but the interwebs prove clear as mud on this.

[achb5]

[QUOTE=JnormS4;10226672]He needs to save, clear then see what comes back.[/QUOT

will do tomorrow, thanks to all for your help thus far!

[zillarob]

2 new o2 and 2 codes? I would be double checking the splice job.
The only thing they both have in common is the heater power, and you would have a ton more codes if that was a prob.

To check the harness, you need to look at the wiring diags and check continuity pin to pin (o2 connector pin to ecu connector pin).
https://drive.google.com/file/d/0B_z...ew?usp=sharing

O2's are tough to check with just a voltmeter. Need something that graphs so you can see them switch.

[achb5]

Dang! I think I figured it out. Not only did I use and electrical parts cleaner on the O2 sensor plugs I used dielectric grease all up in the connector! Should have known better. Thoughts on what to clean up the connectors with? MAF cleaner maybe?


Sent from middle of nowhere

[airjawed]

Dang! I think I figured it out. Not only did I use and electrical parts cleaner on the O2 sensor plugs I used dielectric grease all up in the connector! Should have known better. Thoughts on what to clean up the connectors with? MAF cleaner maybe?


Sent from middle of nowhere

Just leave the connectors alone. If when you put new ones in they have issues with low voltage then think about mechanically cleaning them.

[achb5]

Still having trouble with my o2s :( Logged block 33 and on both banks my o2 voltage never rose above .0035. Fluctuated between this value and zero. Engine was warm and test was 15 min in duration. What are normal o2 sensor voltages?

Next I probed the connectors for the o2 with my voltage meter: Pin one is power pin two in ground. From ground pin to positive battery terminal I see 13v but from pin one to pin two I only see 0.08 volts for both connectors? Fuses 5,28,29,32,34 all good.

Is there a relay I need to check?

Thank you Zilla for the wiring diagram. I have no real idea how to follow that thing, all I know is the connectors for the o2 sensors are on page 6. I cant seem to figure out how to trace the wires back from there.

Thanks again to the community any guidance is much appreciated, I really hope my engine wiring harness is not toasted.

[achb5]

^above voltages with car off key off. With key on I see 1.9V from pin one to pin two and 9.9 from ground pin to positive terminal.

[airjawed]

Did you wire the universal connector correctly? Must be wired correctly and you can not use solder... must be connected via the thing that comes with the sensor.

Check fuses.

Get a copy of the Bentley manual(available online as a pdf). There is a section on checking oxygen regulation... includes checking sensors via VCDS and also with a voltage meter.

[achb5]

Did you wire the universal connector correctly? Must be wired correctly and you can not use solder... must be connected via the thing that comes with the sensor.

Check fuses.

Get a copy of the Bentley manual(available online as a pdf). There is a section on checking oxygen regulation... includes checking sensors via VCDS and also with a voltage meter.

Thanks Air,

I have the Bentley, read through your post about checking o2s via voltage meter as well. I havent yet read the voltages across pins 1 and 2 with the car running yet but I will in the am. Did you ever solve your issue? All my fuses are good, im not sure what the associated relay is or if that could be a part of my problem. Also I just used the box connector that came with my universal o2s, no solder. Gray to gray, Black to Black, and the two white to the two white.

[zillarob]

Fuse and relay are good or you would have a stack of codes.

[airjawed]

Thanks Air,

I have the Bentley, read through your post about checking o2s via voltage meter as well. I havent yet read the voltages across pins 1 and 2 with the car running yet but I will in the am. Did you ever solve your issue? All my fuses are good, im not sure what the associated relay is or if that could be a part of my problem. Also I just used the box connector that came with my universal o2s, no solder. Gray to gray, Black to Black, and the two white to the two white.

My issue was caused by me using electrical contact cleaner. The liquid wicks down the wire and ends up ruining the o2 sensor elements permanently. So, I just got new universal ones and everything is fine. Looks like you made the same mistake along the way. Is there a chance your wiring on the o2 side is still saturated?

[achb5]

I cleaned them really well, but I for sure did use electrical contact cleaner. I'll order two new sensors before I try to dig into the harness.


Sent from middle of nowhere

[zillarob]

Harness is easy to check continuity on.

[airjawed]

I cleaned them really well, but I for sure did use electrical contact cleaner. I'll order two new sensors before I try to dig into the harness.


Sent from middle of nowhere

I agree... I would not go looking for "zebras"... unless the car has had engine pulled a lot of times or crashed I doubt the harness itself is bad. It is possible but just do the oxygen sensor regulation tests section in the Bentley if new sensor(or known good sensor) does not solve problem.