I thought I would split this off from my heater pump repair thread so it would be easier to find in a search.

Ok this issue started after I replaced my heater pump, I think I broke (open circuit with the cable) one of the lambda sensor wires when replacing the pump, or perhaps it was a coincedence.

Any way the result was a yellow engine check light and a P1647 trouble code.

From the repair manual I got this.

Description

P1647 Left-Hand ECM HO2S control
malfunction
Possible source
HO2S heater failure
HO2S sensing circuit; short
circuit to ground, short circuit
to high voltage, open circuit,

Action

For HO2S tests, GO to Pinpoint Test J. and GO to
Pinpoint Test K. Contact dealer technical support
for advice on possible ECM failure

So the problem is with the lambda sensor under the coolant header tank, all four lambda connectors are tucked away behind the trottle body and are tricky to get to. The wires from the sensors go to connectors which are mounted on tabs. The connectors have to be pulled off the tabs before they can be seperated from the wiring loom. They can not be pulled off easily as there is a small notched tab holding them in place. Use a very long screw driver to release the tab and then pull the connector off the metal mounting tab.



Once off the two halves can be separated by squeezing the latching lever.



Next I measured the resistance between the two sets of silver and gold pins. Both sets of gold pins read open circuit (the sensor) and on the right bank (the good side) the silver pins were about 2 ohms but the left bank (bad side) was open circuit.



I tried swapping the connectors over to see if the fault code followed the sensor, it did, the fault code changed to P1646 and the back to P1647 when I put it back to stock.

The conclusion is the sensor has gone bad or the wiring has gone open circuit, either way a new sensor is needed.

I bought this item, it was at a great price £20, however don't buy it, you will see why later.

UNIVERSAL LAMBDA SENSOR (OXYGEN SENSOR) 4 WIRE HIGH QUALITY | eBay

Now to get the old sensor out you wil need to remove the coolant header tank, I emptied the tank using a turkey baser first, then remove the two small hoses from the top of the tank, then the hex screw holding it place, then the level sensor electrical connector and finally the large hose from the bottom of the tank.

Now on the the sensor itself, you will need a lambda sensor socket to do this, mine had a 3/8 square hole in the end and a 25mm bolt head shape.



First I tried fitting a breaker bar, it would not fit in the space available.

Next a 25mm spanner on the end of the lambda socket, but there was no access to turn it.

Then I used a 3/8 socket ratchet but I could not get any purchase on it.

Finally I used the spanner on the end of the ratchet and it easily freed off the sensor.



Next on to fit the connector from the old sensor to the new one, it came with a guide indicating which wires to connect.







Fitting was the reverse of the above.

Once all back together I started the engine, cleared the code, turned off the engine then restarted, no engine check light but when I checked on the tester the fault code had returned. I then did some driving cycles and code clearing, after a few starts the engine check light came back on.

I then checked the resistance of both sensor heaters, the right had side was 2 ohms, the new sensor was 8 ohms. So I think the new sensor resistance is too high and triggering the fault code.

What a pain.

I will need to source another sensor and repeat the process, next time I think I will be able to swap it in 20 mins though.

 

Check some of the threads by JagV8 ... he has found that there is a cheap substitute.

 

I emailed them today to ask what the resistance value should be.

Has anyone noted the resistance of theirs before fitting?

 

The upstream sensor in your car is a wide band O2 sensor (uego) type, not to be mistaken by the downstream standard narrow band O2 sensors (which you probably have bought), these are usually much cheaper than the uego versions.

 

Er, not sure I really did find cheaper, but mainly because I've not needed one (yet). The confusion may be that for some crazy reason there are universal (meaning generic) and universal (meaning wideband or linear)!! You need the latter for the upstreams on a 4.2 (well, you do on an S-Type and I think on any of the cars with the same engine). Peering at the Electrical Guide shows a different symbol in the two types of lambda sensors - when they ARE different. The upstream (wideband) are used because they make fuelling control much better. They're not used downstream because the extra cost isn't justified.

I expect you can buy any part that's the right kind, and I hope parts suppliers can help if you can tell them the jag part #.

 

In the end the seller offered a refund so fine, the seller said it was a wideband sensor but the issue is with the heater resistance which was ~4 ohms.

Cold measurement of the Jag/Denso sensor shows the resistance as 0.9ohm.

So avoid this item UNIVERSAL LAMBDA SENSOR (OXYGEN SENSOR) 4 WIRE HIGH QUALITY | eBay

I also spoke to another owner who tried this one which also did not clear his P1646 code. So avoid this one too. NEW Oxygen Lambda lambada heated 4 wire O2 sensor,1yr warranty,next day delivery | eBay


I then tried two from a salvage yard, both of these were open circuit on the heater too.


So finally I bought one from Eurocarparts for £76, a Denso DOX-0430 (MADE IN SPAIN), it measured 0.9 ohms too, it is now fitted and working perfectly.

 

can somebody tel me wich is the bank 1 and which is the bank 2 on a jag x type 2.5l v6 (2001)

i must to change oxygen sensor ,bank 1 sensor 2
sorry for my english

 

Bank 1 is the right side, from the driver's seat.

Oh! . . . wait! You said 'X' Type. Isn't that a front wheel drive? If so that would be the firewall side.

 

I would just like to add that i have been going mad trying to clear a 1646 fault code, and having discovered this thread, i have changed the universal sensor for a denso one from eurocarparts, and the fault has now cleared, let me echo this author....
DO NOT BUY A UNIVERSAL LAMBDA SENSOR!!!!!!!!!!

 

I have the same code but having trouble finding the location of the bank1 sensor. Can you help?
04 jaguar s type v6 3.0L

 

on my 03 XK8 my upstream drivers side 02 has 4 wires on the connectors.

 

It doesn't help that some places say "universal" meaning "fits all" (which they don't), whereas others mean "wideband" (aka "linear"). There are 2 basic types, wideband being the more expensive with very different characteristics to the older technology kind. They are NOT ever interchangeable so there cannot be a "universal" worthy of that name. Any UEGO is a wideband/linear - "universal" is a stupid name to give it.

 

the sensors are fairly obvious to spot, plugged into the catalytic converter and the manifold, try looking on ebay for a breakers yard selling a complete engine, hopefully a good photo will show their location.buy a proper replacement, i originally bought a universal one, but the heater wasnt quick enough and triggered the fault code.

 

Grab JTIS - workshop manual - and Vehicle Spec PDF, both free via S-Type forum.

 

I have a 2003 xk8 and I have been having some issues with the o2 sensors, "System not ready code" and now a check engine light. I bought a reader that plugs into the module and it showed a code for both sensors as being slow reacting of a sort. It has been awhile and I forgot the codes and quite frankly, in NJ, it has been to darn cold to go out and work on the car. What I find strange is that both would "Go" at the same time. I have not seen a mileage degradation or performance issue as of yet.
1. What other part could be giving the issues?
2. Is there a Ford part number for the O2 sensor and would that work since this is a Ford engine? Would it be less expensive?
3. Where are they the O2 sensors located?
4. Am I better off buying new ones and install to troubleshoot by parts replace?
5. would this also be the issue for "System not ready?" (got this before the check engine light came on....everyone said to keep driving and it will reset.....2000 miles later it has not.

 

Thanks for the thread and photos. I've just spent today fixing a P1647 code that appeared on Thursday morning, the instructions here helped enormously.

A couple of additional observations:

On my car the o2 sensor seems to point much more straight back towards the bulkhead meaning less space to fit that special tool, which I couldn't get hold of anyways.

I removed the heat plate and also the mounting bracket to fully reveal the base of the sensor.

Unfortunately I made the school boy error of trying to use an adjustable spanner as I could get one on it, but all it did was round off the 'nut' of the sensor. So I've spent about 3 hours just trying to get the sensor out. I SHOULD have just bought a 22mm spanner when I picked up the sensor, you only need something decent to 'crack' the sensor loose, but you do need something proper to do it.

Anyways, all done. Hopefully I won't have to be under the bonnet again for at least a few weeks. With having fecked around with the supercharger and now this for the last 2 months, the neighbours must be wondering what kind of old shed I've bought myself.

Tomorrow I can do the job I actually wanted to do this weekend and fit a DAB radio.

 

 

After trying to save money with inexpensive O2 Sensors that did not clear P1646 and P1647 I bought these four O2 sensors.

My Jaguar XK8 as indicated on British Parts UK https://www.britishparts.co.uk/jagua...lectrical-c123
called for XK8 & XKR 4.0 & 4.2 all 1998 to 2006 from vin 031303 -

• Denso Oxygen Sensor - Part No. C2S51801 Upstream - bank one and two - - about $100.00 each

Advance Auto called for these two sensors https://shop.advanceautoparts.com/p/...936/15470524-P

• Bosch Oxygen Sensor Part Number 15936 Downstream - bank one and two - - about $100.00 each

Codes cleared and the proper voltages generated emitted by the OT Sensors. See the attachment

 

Okay guys,

Terry Young's post directly above states that he cleared his P1646 code (the same code I am currently battling) with a Denso C2S51801 (also known as a Denso 2349029 on both amazon and rockauto). He states that it is the correct sensor for Upstream Bank 1 and Bank 2 for the 1998 through 2006 cars. According to P1646, I am battling Upstream Bank 1....

This is the exact same sensor that my initial research turned up late yesterday afternoon. Dale says no, it should be a C2P8810. Michael says no, it should be a C2N3717. Anyone else got any ideas??

 

I think the C2S51801 is a supersession of the C2N3717, so they would effectively be the same here.