I am also fighting a knock sensor code for 2 years — and still can’t beat it on my 2002.5 S-Type 3.0 with 290k mi. Hopefully this will be a bit of a continuation of the aforementioned thread. I am writing this post as I understand things so if you see something wrong or weird, please let me know.

History
For many years this car would enter restricted performance mode very intermittently and it would usually turn off before long. Hot weather exasperated the issue. However, the dealer could never reproduce or diagnose so it was driven like this for roughly 120k miles. After about 50k of that, P0333 appeared and I replaced the knock sensor for Bank 2. About 25k more miles and the Bank 1 knock sensor would throw intermittent code, however I never ended up replacing it. Then a couple years ago a rock cracked the transmission drain pan. I replaced the pan and the car ran like a dream after that. No restricted performance, no knock codes or MIL's. It ran like this for about a year and a half before the restricted performance combined with Bank 2 knock sensor fault started showing up again intermittently. We went on a 1200 mi road trip recently and I decided it was time to address the knock sensor(s).

I replaced the Bank 2 sensor with a Duralast from AutoZone. The old one had very poor voltage response via the tap test. Installing the new Duralast sensor on top cleared the Bank 2 code but the car instantly entered restricted performance which remains on 100% of the time along with Knock Sensor High Input Bank 1 code. I figure a bit strange, but Bank 1 is an original part and could be on its way out. Maybe the ECU doesn't like it due to the bias being too large after installing a new sensor on Bank 2. I ordered a Chinese brand because AutoZone was going to be slower () and installed it. It did not clear the code. Figured I'd get the Duralast as I did for Bank 2 but it also did not work.

I went through the workshop diagnosis steps (Pinpoint Test G/H p.1843) and Step one is to test the resistance of the knock sensor for a 180-220 kΩ value and to replace the sensor given any other reading. I read on here that many knock sensors are not true piezo type and will not fall in this range, so I tested the knock sensors resistance. 0L on the new sensor. Strange. I went back to AutoZone and they swapped it for a Santech brand (about $20 more). It also read 0L out of the box but I installed it anyway, torqued to 25 nm. No change.

At this point I have my original Bank 1 sensor which reads ~200 kΩ and passes tap test on the bench but has small cracks in the insulation around it, a Chinese brand Bank 2 sensor that reads 4.5 mΩ, a Duralast Bank 2 sensor that reads 200 kΩ (installed), a Santech Bank 1 sensor that reads 0L.

Completed Electrical Checks

• Note that B denotes engine Bank. Thus, B1G denotes Bank 1 Ground, B2S denotes Bank 2 Signal, etc.
• P test points correspond to ECU pin-out numbers (p. 25) found in Engine Management Wiring Diagram (p.51) and tested from the loom (ECU disconnected).
• Bank 1 is Knock Sensor 2 (pax side of engine near starter) and Bank 2 is Knock Sensor 1 (in vee under intake).
  • TSB 3.0 L V6 Knock Sensor Designations – Not Based On Cylinder Bank Designations – Clarification
• I put some crank position sensor readings in there too since I thought they shared the same ground but as the manual tells us, this is not true.

Additionally, voltage on knock sensor signal (sensor unplugged, ign. on) ~4.5V and I can't recall what/if I found voltage on the ground. I doubt it or I would have been more inclined to put it in my notes.

Where We Are Now
I've disconnected the alternator com connector, crank position sensor, O2 sensors and Bank 1 knock sensor and removed most of the wire wrap. I don't see anything that looks too bad. I did see an old repair on B2 knock sensor ground, but it was all soldered properly to the shielding, heat shrinked, and in really good shape (until I cut it open to inspect).

My next tests will be to connect the old Bank 1 sensor and see if that resolves the high input code. Otherwise, I will feed Bank 2 into Bank 1 so the ECU should see exact values for both circuits. If that resolves the MIL then I will know almost for sure that the ECU does not like the sensor. Hate to go buy another sensor not being for sure it is the problem or even the right sensor, especially since this began looking like a short.

If that still fails, there is an 03 ECU in a junkyard near me that I may give a whirl, though I am not sure how swappable they are?

Anything else I should do next?

I was going to snap some photos but I didn't get to it. Happy to do so if it would help.

Thanks!

 

I cleaned up the old Bank 1 sensor, slathered the rubber and wire with liquid electrical tape where it was cracking and reconnected it. No code, so I cleaned and buttoned everything back up. Spraying all connectors with contact cleaner and slathering some more liqui-tape on some mouse gnaws I found on a O2 sensor ground in the process.

I didn't bring out the torque wrench and just went hand tight + a rat's *** hair, figuring better to be slightly under torqued than over for testing.

I drove it about 65 miles the next morning to work and she performed flawlessly. For lunch I took it on a spirited drive up to our local ski area. Roughly 30 miles round trip and a 3000' elevation gain. At the top, I shut her down for about 10 mins while I ate. Hitting the ignition to leave the CEL and Restricted performance was on again. I dug out the scanner to see what was going on. By the time I got the scanner hooked up the Restricted Performance had gone away and the only codes showing up were Lean Running Condition or something or other. That was easy, that stupid red suction nipple off the back of the plenum.

It has been working fine since with about 100 more miles on it. I added another *** hair with the torque wrench to bring it a bit closer to 25nm. So far so good.

Conclusion
I wish I could say for sure the root cause was of the Bank 1 code after installing Bank 2. It could have been dirty/bad contacts, some other very well disguised wiring issue, or the failing knock sensor insulation.
What it seems we can say for sure is:

• Resistance on the sensor matters - Jaguar was not joking about 180 - 220 kΩ on the sensors. If they don't read this out of the box, don't even bother it seems. There is a thread here somewhere with a list of reputable brands, at least for the v8 model IIRC but I can't find now .
  • Duralast (worked for Bank 2 (200kΩ) but Bank 1 sensor did not (0L on my meter))
  • Santech Bank 1 sensor did not work (0L)
  • Chinese Bank 2 sensor did not work (4.5Ω)
• Bank 1 and Bank 2 Knock Sensors are Electrically Identical and may be swapped (depending on your splicing and/or connector repair capabilities).
  • Don't forget to buy/replace based on Bank number. Jaguars "Sensor 2" is for Bank 1 and "Sensor 1" is for Bank 2. Think about everything in terms of banks and it will save you a headache; but in Jaguar Books, if they don't explicitly state Bank, presume they are speaking of Sensor #, such as on the wiring diagram.
• Lower torque is fine. Safe to treat the 25nm spec as an upper bound. You can always go tighter but you can't undo a broken crystal.

 

Good work. Way to stay with it. My experience with o2 sensors were as follows in case you need a different perspective in the future. My car is 06 s type r v8 supercharged. O2 sensor function should be quite similar. I was getting an o2 sensor code for upper ones. I replaced both with denso and all was well. A few months later i did a code read for car and got bank 1 cat below efficiency but it did not set mil. I ran some cataclean thru it and some techron cleaner. It took over a year for the cat code to reappear so i did another chemical add. The bank 1 cat is iffy i think but the cleaner keeps it good for at least a year. Bottom line is a marginal cat can throw the fueling math off a bit i think. I never got a flashing mil so i feel good about cats living longer

 

Great work, gunnerman.
Greater yet is your write-up, for which many, now and in future, will be very thankful.

Cheers and best wishes,

 

Funny you should say that. Yesterday, I wound up in 30 mins of stop and go traffic and guess what came on...Bank 1 Cat Below Efficiency. I am hoping they just got a bit of build-up due to the weeks of driving never over 3k rpm that will burn off with a bit of zoomzoom. I'll throw some cat cleaner in and see how that does (or unhook a suction line for a bit ).

This car had the cats go out on it once before around 150k. No explanation other than the dealer saying non-premium fuel was used (incorrect). Just as they had no idea about the Restricted Performance. Of course, years later, approaching 300k miles, everything finally starts to piece together.

 

Just a remark on the "liquid electric tape", which you used. I am not sure, if it is possible, where you applied it, but in general I found that the best solution to renew insulation is shrink tube. For really good insultation, two shrink tubes over each other. Shrink tube comes in all sizes, even really massive, and it comes in shrink ratios of 1:2, 1:3 and 1:4.

Furthermore, where you want to protect wires from the heat of the engine, you could also put some corrugated tubing on as well.

 

I agree, shrink and corrugated tubing is the way to go. It is what I use for most repairs. I also like to wrap the corrugated with foil tape. Keeps things cool and makes it much harder for rodents. I mostly used the liquid tape on things I didn't want to cut or disassemble connectors for as a it's on the shelf, might as well use some.

If the car didn't have 300k on the clock already, I wouldn't have gone slathering liqui-tape all over.

I just drove her a few hundred miles up to Pagosa Springs and it made it nearly the whole way before the MIL came back on due to Cat inefficiency. May be time to start looking for that v12 they say I'm supposed to own one time.