Vectra O2 sensor - more

The story from the top....

Lots of issues (codes) being generated by the OBD. Cruise had stopped working, dash reporting brake switch had failed. He took it into garage and they replaced the front O2 sensor and fitted a new brake switch. Later is two pole, one for brake lights other for ECU(?).

Had thought with all of the codes randomly being generated, that the ECU was failing.

It came back with pretty much the same faults showing, so we had a another look at it, thinking the brake switch fault and cruise failure might be related to the cruise ECU having no supply. The manual didn't suggest which fuse powered the cruise, so went through every fuse in the car, looking for any which were blown. Found one which had blown and replaced it.

That fixed most of the issues, cruise brake switch and all of the fault codes, except one. Performance now much better. Not happy about the garage not noticing the blown fuse, replacing a perfectly good brake switch and maybe the O2 sensor. It now complains Oxygen sensor 1, bank

1 heater and an occasional fuel trim code. Checked resistance of the heater and it showed 17 Ohm, which is within spec. With engine warm and O2 unplugged, checked for voltage feeding heater, measured 0.4v. What I don't know, is should the heater circuit be switched off by the ECU, once the engine is warmed up.

Any other suggestions welcome please.

Reply to
Harry Bloomfield
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Harry Bloomfield expressed precisely :

A bit of progress...

This morning started with a P0135 (O2 heater fault) and P0130 O2 sensor fault. We then decided that the pin out at the plug was WRONG and corrected it. Which cleared the P0135, but still left the P0130 code appearing. Now thinking that the sensor was faulty, or maybe damaged by the wrong connection.

Reply to
Harry Bloomfield

Harry Bloomfield has brought this to us :

It seems to be all sorted now :-)

He has had it out for an essential run, returned and the pending P0130 is not coming back. My absolute guess is that due to the heater not working and no doubt the sensor side, the O2 sensor became choke up and needed a run to clear the O2 sensor.

Reply to
Harry Bloomfield

Harry Bloomfield wrote on 06/01/2014 :

Spoke too soon :-( It came back when the engine was started cold, so swapped the front sensor for one which had been working fine at the rear, but even then it still showed an occasional pending fault, but nothing stored as a fault. Running out of ideas!

Reply to
Harry Bloomfield

Which was showing the new pending fault, front or rear? If the fault is still at the front then it could be a failing/damaged bit of loom. After that maybe moisture or crap at the ECU end of the connector (and that's assuming you've checked out the state of the probe end connector

If the error's migrated then dodgy (or incorrect) sensor, natch.

Reply to
Scott M

Make your mind up, Blumfeld!

Reply to
The Revd

Once the failed fuse had been replaced, the only codes have been for the front sensor. Once the swapped terminals was corrected, it fixed the heater fault code, just leaving this one intermitant fault code for the front sensor.

The car is not here at the moment, but it should be easy enough to check the continuity between.

A schematic for the circuits of the car would be useful, but I have not been able to find any. If anyone has a source please, it would help.

Reply to
Harry Bloomfield

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