Evening All,

In the interim period of my last visit and todays visit, the customer has spoken with the main dealer about the problem. They have told him that it would be "improbable" that an after-market sensor would solve his problem and the first thing they would do is bin it.

However, I pitched up again today and found the following:

1) An additional fault code was present which was PO134 - HO2 sensor circuit.

2) I watched the heater operation on my scanner from cold and at all times remained "off".

3) The 02 content was down to normal at about 0.6% at idle and a bit lower at fast idle. Lambda reading was within MOT limits at 0.99. The leaking exhaust joint had been fixed.

4) The CO level at fast idle was now 0.4% and on a second run at 1.4%.

In view of the foregoing, I took the easy way out, the customer is happy to invest in an OE sensor. This decision was based on what the customer had been told by the stealers and the opinions voiced in this thread. Also, if the new sensor did not fix it, then the fault as I see it would lay in the wiring loom or ECU which is something I am not comfortable to be involved with. Also, the MOT expiry date was getting close and the extra time spent with me testing further and posting findings and awaiting helpful hints would push it past the MOT expiry date.

Now normally I would test an expensive sensor to the Nth degree before replacing, but in this case due to the complexity of the situation, I have made an exception to the rule. The customer will advise me of the outcome.

Finally, thanks to all for your helpful advice and also Dave Harney who rang me this morning.

Regards

Pete M