Love my first Jaguar 1997 XJ6 4.0L- But can't Register B/C Stubborn Knock Sensor P0326 P0332 Plus mystery P13B0 and B30F4

Hi Everyone,
I recently bought my first jaguar. It’s a 1997 XJ6 straight 4.0L in beautiful condition. It was owned by an older gentleman and spent years just sitting in his garage in CA. I got quite a deal on it. The car starts and runs well. However, I can’t register it in CA until I can figure out how to fix the check engine light so I can pass an emissions inspection. I am getting desperate.

When I first bought it, I had autozones check the codes and it showed P0326 and P0332 knock sensor codes. It also showed pending P13B0 and B30F4. The car also made some noise at higher RPMs that I was thinking was related to the knock sensor codes. However, it turned out the noise was coming from the timing chain tensioner sticking and I was able to fix this issue by pulling it out and cleaning it up. I also removed the wire harness on the front knock sensor and checked for corrosion. There was none. I did hard reset by removing the battery and took it out for a drive.

Unfortunately, all of the codes came back. I read in other forum posts that the pending P13B0 code was likely the bank 1 downstream O2 sensor (now I doubt this). I ordered a new O2 sensor, bought my own scanner (an innova 3160), and ordered one used knock sensor($50) and one new one($130).

Parts arrived. I replaced the bank 1 downstream O2 sensor. Then I pulled the old front knock sensor off. (I had a hard time reaching the rear sensor which is behind the starter so I left it in place.) I checked the resistance of old front sensor and the two replacement ones I had just ordered. All three knock sensors read about 1.05 M Ohms. (I don’t know if this is that meaningful. I think the knock sensor is a piezo-electric that converts the sound vibrations into a voltage pulse-but the resistance being the same for all three seemed to indicate the old one was probably ok. Anyway, I installed the new sensor in the front and reset the computer. I drove the car around with the new sensor in the front and the orignal rear knock sensor in place. After about 50 miles the codes all came back. I posted pictures of what my scanner tells me below. I get all the monitors to set except EVAP and CAT. The new scanner has a live feed mode too where I can see the voltages coming from the O2 sensors are bouncing around, which I am told that they should.

I am at a loss of what to do. I live on a college campus and can’t park the car here until it is legally registered. Without getting the monitors to set I can’t pass an emissions test and am not able to register the car, drive it, or even park it on the city streets. I do have a one day permit to drive it to a shop that I am supposed to use a pen to mark the date on. I am waiting to get pulled over to pen the date in. I am taking my chances that it won’t get towed off the street. It’s the only parking I have. This has been going on three weeks where I try something like cleaning the contacts etc. Nothing I have done has worked. I keep driving it so it certainly doesn’t look abandoned.
The only other thing that I can see is there there appears to be some oil residue towards the front of the engine but this is far away from the knock sensors which look clean. The alternator seems to keep the voltage 13.5V. Any ideas? Anyone had a knock sensor code that persists even with new knock sensors? Anyone know what the heck the pending P13B0 and B30F4 codes are? Is the fact that they have letters where the numbers are supposed to be a problem with my scanner? Or is that the actual code the ECU is putting out?

Thank you in advance for any advice. I have only a moderate amount of experience as a mechanic.

IMG_20191013_072434|666x500 !

Sorry I am a new user, so I had to remove the other images…I am only allowed 1.

I don’t know if this is going t help but a quick google search came up with this;

The B code indicates a body code

Thanks Robin,
I did a ton of searching last night and it seems that maybe the B in the P13B0 code is a 4. I guess this could be a code reader issue(Even though both my reader and autozones reader give the B). If the B was a a 4 then it would be the camshaft position sensor. P1340.

Is there a way to test the Cam sensor?

If the camshaft sensor is faulty then the car will normally take longer to start than normal, as it tells the car when it’s on a compression stoke.
It will work it out, it just takes more turning over.

Thanks Pete,
The car starts right up with no delay. There does seem to be a small delay when accelerating.

There are 3 knock sensors on the AJ16?

I’m all in on seeing if we can get you to clear those codes. I’m assuming you have the ability to pull codes on your own? It’s a cheap device you can buy on Amazon, or you can buy the wireless ELM27 plugs to make it work with your smartphone.

Anyways, I believe you have two knock sensors. I’ve never heard of the knock sensor code being thrown, but I’m glad it does. These engines are so stingy with their codes…

I think you mentioned you bought a replacement knock sensor. Your second code shows that it’s Bank 2’s sensor that went bad. I’m assuming you replaced that one? I believe it’s the one closer to the firewall. (The spark plug/coil pack holes are numbers 1,2,3,4,5,6 from the radiator (#1) sequentially back to the firewall (#6).

You mentioned buying this car from an older man who had this car sit for a long time. I’m assuming you’ve already burned through whatever fuel was originally in the car? Hopefully a couple of times?

Hi Veekay,
No there are only two knock sensors on the car. I orginally had taken out knock sensor bank 1 (front) and had bought two extra ones. A new one from ebay and a used one from ebay. Sensor 1 taken out of my car had the same resistance as the two ebay sensors. I have a code reader (innova 2180 I think). It has live feed diagnostics in addition to code reading and clearing ability. My original $15 reader couldn’t communicate with the xj6 so I bot this more expensive innova. Yes, I have burned through about two tanks of gas and it is almost empty again. I will take it down close to the empty line and then put premium in it. I haven’t yet pulled out the plugs, but I am planning that today. Should have already done it, but I only get about 2 hours to work on it each evening and I can’t leave it apart. I was keeping it on a back street across town. I don’t have a garage or driveway as I live on a college campus and they don’t allow parking an unregistered car here. Sorry too much info, but my situation keeps my progress slow.

I should probably pull and replace the plugs. I think I should also get a new valve cover seal and the rubber seals for the cover bolts to prevent oil leaking as others have expressed. I was bent on fixing the knock sensor codes first P0326 corresponds to he front. I have new one in there. P0332 corresponds the bank 2 rear and I the used one from ebay I put in there. It takes me about an hour to put he car up on jack stands, remove a hose and oil filter, and change the first one. I can remove and replace the second one in 15 min. If i were quick and easy I would just swap the two, but the real slow part is that I have to put between 50 and 100 miles on the car before the codes reappear. Even with sensor 2 cable completely unplugged the ECU doesn’t through a code immediately.

So right now I am trying to be strategic with my tests. I have continuity tests planned for this evening on the knock sensor harnesses from the ecu. I have been getting feedback from a similar thread I started on Everybody has been extremely helpful despite my rookie questions and I am greatly appreciative of feedback like yours. Thanks, and I will check the plugs too. I guess the computer has just had me focused on the knock sensors which may be fine. Still, if the knock sensors were detecting knocks I think I would be getting over-voltage codes and not undervoltage codes.
Thanks again. I will provide an update soon.

Are you confusing the oxygen sensors with the knock sensors? The knock sensors are on top
of the engine. They should be very easy to access and replace.

Oxygen sensors are under the car.

Spark plug replacement is easy and really shouldn’t take an hour. It’ll also let you inspect the coil packs and make sure you have no issues there.

We have to make sure that we address and kill off that knock sensor code before we attack anything else. Nevermind those oxygen sensors right now. I can’t see how they would have anything to do with setting knock sensor codes.

I’m assuming you’ve been using premium fuel all along…

So I finally got around to changing the plugs and the plug and coil #1 were submerged in oil. Coil number 1 has also been replaced in the past. I ordered a new valve cover gasket and spark plug seals. I replaced all of the plugs.

No I am not confusing the oxygen sensors and knock sensors. I have replaced both knock sensors and checked resistance of the sensors through the harnesses, so I think the knock sensor circuits are okay. Also I think the knock sensors are okay.

Based on adifferent thread I replaced the bank 1 downstream O2 sensor because I thought it might be related to the P13B0 code coming from my innova 3160 code reader. Code came right back.