I have a 2005 3.0 AWD

I took the car in for inspection and I was told that my lambda values are too high to pass inspection and that they need to be exchanged.

I took the car back to my service guy and in his opinion I don't need new sensors, rather the car has an electrical problem. The engine light comes on the front diagnostic panel, but he is able to
make it disappear. Also, ever since I changed the alternator. the diagnostic light comes on showing the battery is not being charged, but I am able to drive with it.

Any ideas about the lambda sensors or the alternator?

 

JagHU, the first thing I would do is get my hands on a multimeter and put it across the battery terminals (only touch the lead part of the battery, avoid the metal part of the battery cable). With the car turned off, you should see 12.5-12.6 VDC (if you have the door open, it will be 12.5, door closed, 12.6). If you don't have this, then you have a problem with either the alternator or the battery. If you have a low voltage, put the battery on a charger before continuing. Once you have the battery up at 12.6 VDC, start the car and do another measurement. Depending on how fast you are getting around to the battery, you may see it as high was 14.4 VDC, but after a minute or so, it will fall to 13.7 VDC (have all electrical stuff turned off). If you have something less than that, then the alternator may have an issue. If you have a low voltage, turn on the seat heaters and rear defroster (puts an electrical load on the alternator). If the voltage remains constant (what you read before), then the alternator is good. If it drops significantly (ie to around 12.5 VDC), then you have a failing alternator. If you find something else, let me know and we can take things from there.

As for the lambda sensors, if the voltage in the car is where it should be (ie, 13.7 VDC with the engine running), then odds are, you have lambda sensors that are getting old and need replacement. You can try running a tank of high RON gas and a bottle of throttle body cleaner and be a little bit aggresssive with how you drive (don't get any tickets). But, you want to get the exhaust temp up some to help burn some of the gunk off of the lambda sensors. But, odds are, you will end up replacing them to pass inspection.

 

Thank you for your quick reply!

Thank you very much for your help!

I have a new alternator from the UK for 100 Euro and I have a new battery in the car. Someone rebuilt the old alternator, but afterwards the red battery warning light showed up on the dash that the battery wasn't charging. So, I bought another alternator from the UK thinking the rebuilder of the original didn't do something right. Now I still have the same problem that after I start the car, after about 5 seconds, the battery no charge warning lights up on the dash, but the car runs at 12.5 V.

I drove 100 km at 150km/hr with 100 octane gas and it didn't solve the problem before the test. So, I guess I was on the right track, but it didn't resolve the problem, so I will change the front sensors and see what happens. I can only assume there is a short in the sensor wires.

A Jaguar service guy told me that only an original Jaguar alternator will work in the car. Is that true?

 

JagHU, from our experience, that is a fairly true statement. Jaguar has done something with the alternator to make it very touchy. What it is, I am not sure of.

 

A properly working / properly repaired alternator should (obviously!) not put the warning light on.

Jaguars have smart charging systems to prolong battery life despite all the electronics in the car posing such heavy loads, and the light is an indication of a fault.