Passat Diagnostics

[derekdublin]

I have just returned from having the diagnostics run on my car. In Sept 05 the light first came on & my mechanic installed a new Oxysensor. An hour after collecting the car, the engine warning light came back on. He reset the computer but it came back on again so I took the car to an official VW garage where I'd bought it and they too replaced an Oxysensor, (charging a hundred euro more for the privilige). Yet again, the light came back on after about an hour or so.

Since then the light has been on. The diagnostic reads today, Feb 10th;

ECU Info: ISO9141 Protocol detected.
KeyBytes 08 08
PID's 19
(BR 10465)

LIVE DATA
RPM

Errors present
P--P0141 Sens. circ. B1 S2 s.heater

My mechanic reckons its the 2nd Oxysensor at the back of the cat that requires changing this time & that both he and the VW garage had changed the same Oxysensor the first time, ie the one at the front.

Any ideas?

[Col]

Sounds like the heater supply or earth to the sensor B1 has gone open circuit to and I doubt it is the sensor at all.

[Col]

Let me know what your engine code is and I'll have a look at the wiring diagram and let you know which pair of cables you will need to test on the sensor for continuity to earth and or 12v supply. (could be 5v)

[derekdublin]

cheers col, is that a big job? can u think why he thought it was the oxysensor? is the diagnostic very accurate/specific or does it just point you in the right direction?

[derekdublin]

I think the engine code is WVWZZZ3BZ2P064183
The followin details are in the book i got with the car;

3B30B1 ALZ

hope this is useful, & thanks for advice/help

derek

[Col]

cheers col, is that a big job? can u think why he thought it was the oxysensor? is the diagnostic very accurate/specific or does it just point you in the right direction?

The diagnostic is spot on.

If you look up that code, look here....

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

...you will find that that code is applies to the heating circuit with the B1 sensor.

This can be the sensor itself (the heater side) or the wiring to it.

The sensor side of the sensor will vary between 0v and 1v, the heater side could be 5v or 12v, you should be able to unplug and measure both with a good multimeter. Obviously if your getting voltage in the cable it will be the sensor. You can buy the sensors fairly cheaply but will need a special socket to remove / install.

[Col]

The sensor downstream of the cat, known as the G130 for the heater circuit has;

green / yellow

and

red / white

cables.

The green / yellow is a 12v supply.

The red / white is the return to the ecu .

The other two cables form the sensor circuit.

[derekdublin]

Col, I have to say, a lot of that goes over my head but I have noted it down & wil take it too my mechanic tomorrow. I really appreciate ur time & effort.
So all the best from a miserable dublin where Iv just broken my nose playing soccer! Derek