I bought my car displaying a P1646 code which will be the first thing to fix.

Have worked myself through the (sometimes confusing) info, but deciphered that for my 2003MY XK8 (N/A):
bank 1 = right side / easy side
sensor 1 = upstream O2 sensor
original O2 upstream sensor is a DENSO 234-9029
​
As I am on a little island, and everything needs to be shipped, with difficult returns, is the above correct?
Appreciate a lot if anyone can confirm before I place the order.

Eric

 

Looks good to me, I ordered/replaced the same part based on the same code a while back. A crows foot O2 tool worked perfect for this.

FWIW, check the fuse and relay for the heater circuit first to make sure the sensor is even supplied power...

Best of luck, keep us posted.

 

Well, that was worth the try, but they showed all ok.
I also got a NO DATA for the right upstream sensor on my Torque app, so just ordered the DENSO one.
Thanks for the re-confirmation.

 

That sounds like a Torque or the OBD device fault.

 

It runs perfectly on my X308 with same hardware.

What should Torque display on a broken Upstream sensor? Just zero?
I got a returning P1646 code (indicating the same upstream sensor), half of the time the NO DATA shows.

 

It would depend in what way it's broken and then what the PCM decides to do but if the OBD tool can get LTFT it should also be able to get STFT values.

Somewhat irrelevant given the code! Any data would be meaningless. If you're lucky the PCM will be using the data from the good bank to do AFR for both banks. (Generally, the PCM wants to protect the cat conv but not at the expense of ruining the engine by running too lean.)

I expect the bad bank is flagged as OL-Fault (or the equivalent wording) and any time you have that the actual O2-related data for the bank can be meaningless.

 

I was actually wondering about that.
Is it like you say, or is the system going into an open loop mode (using the ECU base fuel mapping) in such case?
I really have no idea.

I stopped driving the car till I get my sensor and suspension parts, but she drives perfect, no one should ever know something was broken.
Even the fuel consumption is not noticeably off (still a lot, not a super lot).

 

It could do either - but it'll not be ideal if it stays OL as it will run somewhat rich and that's going to shorten cat life the longer it continues.

You sound to be on top of it, though.

 

Installed the new Denso O2 sensor, and all circuits for both banks are working / diagnosing again.
Presume a broken O2 sensor most likely disconnect the whole closed loop workings.
Thanks for the help here!

 

I got used one from junk yard. I use autozone.com to check compatibility first, then go to remove it.
It is wide band, 4-wire sensor, same like 03 X-type.
you probably have bad ignition coil which killed o2 sensor. This is what happened on my X-type.
If you have bad coil, you'll be replacing o2 sensors every month.
Bad coil can kill o2 sensor AND catalytic converter.
do you have misfire code?
I had 3 bad coils. they all die about the same time. It could be a few days difference.