Hi all, so when plugging in the code reader for my battery fault it also threw up the P1646 fault code, but said A: heated oxygen upstream bank 1 control circuit malfunction
B: fuel pump relay 2 malfunction.

So is it one in the same or 2 possible reasons for the fault?
Any help really appreciated as ever.

 

It's the o2 sensor driver side unless you have a supercharger.

 

Just occasionally jaguar have used a code for two different things (on different years of the same car or on different cars)!!

It's likely the O2 meaning.

 

Great, I'll check that out and hope it makes the difference. Thanks again for your input.

 

Trust me Fellows I have been looking up and down this forum. But I have not seen any definitive answers to this question. My 2003 XJR 4.0 SC is reading fault code P1646. I am trying to determine which Denso Sensor is for my car. Denso 234-9029 Or Denso 234-9016 ???

 

They may well both be OK if the cable is long enough.

 

Guys take a look at these Sensors Applications

Denso 234-9029 Jaguar Air- Fuel Ratio Sensor X-Type, XK8, XKR Part #EN-2349029Denso 234-9016 Jaguar Air- Fuel Ratio Sensor Vanden Plas, XJ8, XJR, XK8, XKR Part #EN-2349016Bosch 15627 Jaguar Oxygen Sensor Upper Vanden Plas, X-Type, XJ8, XJR, XK8, XKR Part #:BOS-15627

 

Could be a updated change and not followed up on all the part #'s, I'd contact Denso.
Its like me using 4.2L knock sensors on my SC 4.0L ..it doesn't say they work on it, but they do ..at 1/2 the cost.

 

Length of cable, maybe.

I used the "wrong" kind on my STR - it had a somewhat longer cable which I tied out of the way. Hardly a big deal.

 

Check This Out. Click the page . Go to Specs. Notice they are identical.
SKU: #234-9029 ITEM : # DEN234-9029 BRAND : Denso
https://www.densoproducts.com/product.aspx?zpid=18818.

SKU: #234-9016 ITEM : # DEN234-9016 BRAND : Denso
https://www.densoproducts.com/product.aspx?zpid=18805

I called an spoke to a Great guy in Technical Support. This Company has a research and learning advanced product look-up tool. First he checked on his computer system and confirm the specs where identical.
Then he cross referenced the Catalogue. Fortuitous for Us He has Both in stock on the Shelf. He pulled them. Thoroughly examine Both he and said "they are exactly the same product". An has no clue why they where given different Numbers cause they are the EXACT SAME PART. Mystery Solved.
THE END.

 

I Guess I Spoke Too Soon Cause, It's Not THE END
I received this today from

According to my look up, I would suggest a slightly different part number. Note: As an OE supply company, DENSO follows strict guidelines, which are incorporated into our application data.
That being said, it's possible that your initial selection might work, but there is a difference between the sensor cores, which communicates with your computer, so need less to say, I would not recommend using it.
I already ordered the 234-9029 awaiting delivery
What you all think ?

 

It doesn't send codes so what was posted is wrong or at best highly misleading.

 

From; ASK_TECH@densodrive.com

According to the Engineering information available to me, the sensor core between the 234-9016 ('3400 on Sensor) & the 234-9029 ('3410 on Sensor) are not
the same.
The connector & thread size is the same, so even though it will fit, the communication specifications of a '9029 sensor, between it & and your computer is not going to be the same as the communication specifications of a '9016 sensor.
If you happen to have your original sensor, the OE # associated with the DENSO 234-9016 is LNE1684BBG & the OE #'s associated with the DENSO 234-9029 are C2C7359 & C2S51801.

 

Wow talk about drivel!

Marketing-speak gone mad.

 

Just to echo some of the above, I tried an alternative replacement that was suggested in another thread, which by all appearances was identical, however it didn't change a thing, and wasn't until I went with a Bosch replacement that it cleared up my issue.

 

Never mind marketing, this is not my intention. The objective is to share our experiences and info we've collected in the Love, Ownership and Repairs Made on the Ladies. I could care less which company one uses.
My only interest is that we get the correct part at the lowest price.

 

This is relative to the P1646 code O2 Snesor issue I think across multiple models depending on engine/serial/VIN/Year, but I think early in the thread there might have been some bad engine location info?

Does the part number in the Electronic Catalog always cross to a Denso? I don't think so. Most Automotive manufacturers have a first tier supplier but always have other manufacturers in their supply chain to meet or exceed the OEM spec. Even Denso manufacturers their products in China and Taiwan because their manufacturing costs to manufacture only in Japan are quite high, and in fact, the Jaguar Denso's, many come from China or now, India factories ( aka TATA) that manufacture many different OEM brands.
The Upstream Heated PN is LJA1682AE on earlier models and LNE1684BB on later models depending on VIN and Engine Number
The Downstream PN is LJA1680AE on earlier models and LNE1682BC on later models.

I use those part numbers for primary searching and then do some cross referencing for best price in equivalent specification by going to NAPA and having the counter guy compare specs from OE to aftermarket.

Back to location, I believe P1646 is "A" Bank which is - sitting in the car, on the RIGHT side, - which is only the "driver side" if you are RH Drive - but is still the right side of the engine even on LH Drive. I sure hope I am not wrong or I assembled my AJ-27 engine backwards and upside down with the intakes on the exhaust - OMG!!!!

So when referencing engine components, please reference engine locations, not Driver position because engine position is how the Service Manuals reference engine components.


AJ-27 Banks A and B from AJ27 Engine Training Manual

P1646 - Bank 1 or Bank A, P1647 for Bank 2 or Bank B

ANYWAY ...

Having twin XJ8's, a 2000 and a 2001, I can borrow parts on one car to check if the code returns on the other.

For my 2001, before I tore it down for compression/leak rate failures, it had a P1646. After reassembly, I knew I had to verify that code failure to troubleshoot.

So I pulled the A bank sensor (right side sensor on the engine easier for access) from my 2001, swapped to my 2000, and the P1646 moved to my 2000, which confirmed the SENSOR itself is bad (and that Bank A is Bank 1 - that is on the RIGHT side of the engine), BUT, when I put my known good sensor from my 2000 into my 2001, the P1646 code returned in the 2001. That is probably another problem.
On my 2000, I replaced all 4 O2 sensors with aftermarket "sets", but kept them all to the same manufacturer source, after all O2 sensors are consumable items not meant to last forever or be replaced individually for best performance. That fixed all my lean issues on my 2000 instantly. The ECU is looking for the same reference levels cold/heated/operating, so mixing different manufacturers is probably not good practice, similar to mixing tires or spark plugs of different manufacturers

On the 2001, I have checked the harness ( pinpoint tests from the connector to the ECU and the pins and continuity and tests for shorting all passed the pinpoint tests but with a known good sensor, the code returns immediately.

Specific to mine, the 2001 is having issues acceleration which I believe are ECU issues from a Dreaded Previous Mechanic disconnecting the ECU without disconnecting the battery. I had a rebuilt Throttle body on my 2000 that I swapped to the 2001 and the 2001 still has acceleration issues, also MAP sensors swapped, new coils, new plugs, etc with the engine rebuild. Connector pins have been checked, cleaned, changed, etc ...
Remember if you perform the Pinpoint tests, BEFORE you disconnect the connectors from the ECU, you typically must disconnect the battery and allow the system to completely discharge per the pinpoint instructions as to not damage the ECU. Follow the pinpoint test instructions to the letter.

Cheers!

 

As a follow-up confirmation to my earlier suspicion in March 2019 on my 2001 XJ8 X308 DTC, it indeed was a defective ECM/ECU discovered in another post on this forum. The confirmation was made by my local dealer when I asked the shop foreman to dig deeper past the initial errors.

So a reconditioned ECM from Foreign Auto Computer Repair resolved the issues just as expected - but not to say all pinpoint tests should not be conducted first.

Cheers!