Dear Forum,

Bearing in mind that this car (2004 XJ6) will not go into Closed Loop, would the circled O2 readings be the cause of that Open Loop and would the ECU still flag a code (there is no code) if the sensor was genuinely faulty, please? Obviously I do not want to recommend a fellow Forum member replace an O2 sensor unless I am sure it is faulty!

 

Your scanner seems to be picking up incorrect data for a Jag. There is no O2 5 as far as I know, The data for it seems reasonable though for one of the wide range sensors. I think both banks second O2's are wide range.

 

Thank you OldKarz for your response...Unfortunately, it is not my scanner..it is the owners basic OBD11 scanner; please, what does both banks second O2's are wide range mean?

 

There are two types of O2 sensors. The original and most common produces voltage over a very narrow band of rich/lean. The wide band works differently. It produces voltage over a large range of rich/lean conditions. The ECU applies an amperage, to the sensor, to correct the voltage back to optimum. Then calculates the amount of correction dependent on the amount of amperage it supplies to get the voltage back to optimum. You can see the amperage being applied on your O2 5!

 

I had problem with the O2 sensors from my jag XJR x300. But they only was wrongly tightened… If your jag has two sensors you could try to change the connections and then read with the scanner. First of all do not forget to identify the connectors (for example with a tape or something) sometimes the scanners cannot be able to read two O2 sensors…

 

Thank you guys,

I think what I am trying to establish is: Can I trust ANY of the OBD11 readings, given that they are being displayed from an 'Open Loop' engine?

 

Another consideration is whether the car has P1000 or P1111. If P1000 then many codes cannot be flagged because the car (its PCM) just doesn't know what to trust.

 

Thanks JagV8.

I have visited the forum member now with my iCarsoft tool and have found the following DTC's
P1108 & P1646



I am assuming this is why his car is stuck in Open Loop and that he needs a new MAP Sensor & a New Bank 1 Upstream O2 Sensor?

 

I'd change the O2 first and see what happens.

I wouldn't clear the codes (unless you already have) because I wouldn't want to cause P1000 and the code will self-clear after 4 warm ups if fixed.

 

Thank you. I am going to do the Pinpoint tests for voltage and resistance before recommending he replace the O2 sensor.