My 03 XKR has had the restricted performance come up very intermittently in the last few weeks. It appears to be heat related. The Jag dealer checked everything and found that the Number 1 knock sensor is causing the problem as per his code scanner. The dealer wants $1,500 to do the job. I checked out the price for a knock sensor and they run around $45.00. Does it take all that labor time to do this job? It would appear that the whole top of the engine would have to come off. Does this sensor have a connector where I could get to it to check the contacts and clean them. Any suggestions would be helpful. The dealer suggested that I buy a scanner and when the Reduced Power message comes up to clear it out.

Bill N
03 XKR

 

I just did this job about two months ago.

First, yes, the knock sensors connect to the engine harness on both sides of the thermostat tower. Check and clean these connectors with CRC contact cleaner, and make sure they're in good shape. Mine were in terrible shape, degraded by old coolant leaks, torn wire insulation, etc. I ended up not only replacing my knock sensors, but also the connector to the sensors on the engine side of the harness.

Knock sensors can theoretically be changed without removing the intake manifold. Techs do it all the time, so the price you're being quoted is robbery. Look into JTIS for the procedure, and search the forum. There's some info in the archives.

As for me, I wanted to learn more about my engine, and clean a few things up, so I took everything off.

Good news...knock sensor codes are gone...for now.

 

I have the supercharged engine so I would guess it would take a little more work to get to them. I have another repair garage that I called about replacing them. They specialize in Jaguar repair and host some of our meets. A lot of the guys in our club use them. I am waiting to hear back from them for a quote to do this. If the intake manifolds don't have to come off it should not be that difficult a job. I think something leaked on them or the previous owner steam cleaned the engine.

I will get the RP message on start up, if the weather is hot 85-95 degrees and I let the car sit for about 1/2 hour after driving. When I start the car in the morning I can go all day without the problem, as long as I don't stop anywhere. If it does show up it usually clears itself after driving about 20 minutes.

It would be nice to hear from some of the other members that have had this work done and how much they paid. I am thinking about $500.00 to replace the sensors.

Bill N
03 XKR

 

I just talked to my independent garage, Jag service guy. They want around $500.00 to replace both knock sensors. That sounds fair to me, so I am going to have them do the job next week. This garage is well known to my Jaguar club and our members take their Jags there for work. I have not heard any complaints about their work. They have a certified Jaguar mechanic working for them and he is scheduled to work on my car.

I felt that replacing both sensors made sense as they only cost about $40.00 each and will only add about 1/2 hour more to do. I am also going to have two of the top water hoses for my supercharger replaced as I saw some ware on the top of the hoses, caused by them rubbing on the hood liner.

I also just ordered a U480 Can-bus scanner @$14.99 from Amazon. It is just the basics and is on the recommended OBDII scanner list.

Bill N
03 XKR