I am having problems with CEL and restricted performance performance on my 2000 Jaguar XJ8. The original codes are P0172, P0174, P0300, P0301, P0302, P0304, P1316 and P1638. I have changed out all spark plugs, coils, knock sensors, MAF, and Oxygen Sensor Bank 2. I have tried to get new reading on codes and purchased a OBD II but for some reason I am getting NO Link. I have checked all the fuses on the driver side but they are all good.


Please help!!!

 

to get anywhere you will need a working OBD2 code reader to clear the computer and read the codes that comeback. Also, check closely for an intake air leak. No harm in doing a hard reset but that will not clear the codes


Also, what is the background on the problem. Was it running fine prior to all these codes? Was it sitting unused for a period of time?

 

Take it to whomever read codes for you initially: see if they can read codes, if they can but you cannot with your new OBD two reader, then you are not positioned correctly or it is a faulty unit.if they are not able to read the codes, then you have disconnected some of the wiring. More importantly, how was it running before you did the work, and how is it running now?

 

The vehicle was setting up for a year. The car ran hot and after that the mechanic stated I needed a motor. I purchased a motor and had it installed. Once I picked up the vehicle and drove it home all of the codes appeared. That's when I took the vehicle to the shop and they pulled the codes I mentioned in my post. I had the spark plugs, coil, knock sensors, thermostat, thermostat housing and hoses replaced. The car was still showing restricted performance so I purchased the OBD II reader to avoid paying for the reading of the codes again. The reader states no link. I took it to AutoZone for the codes and their equipment showed the same thing, no link. They told me to take it across the street because there was something wrong with fuses or wiring.

 

The folks who did all the work failed to connect something . .

Grab the wiring diagram from the stickies and trace back from the OBD socket. I bet it is the socket to the main power bus or to the ECU. Or the ground . .

How does it run?

 

The 1998 wiring manual lists the diagnostic connector as Fuse #4 in the fuse box in the trunk (in front of the battery). It is a 5 amp fuse. Check to see if that fuse is blown


I am not sure if your car uses the same fuse location or if the "diagnostic connector" is the OBD2 port but worth a look

 

I too am a relatively new member. I originally bought a 98 XJ6 sport, but after a journey ending in a disastrous overheating problem resulted in the Sport being sidelined, I purchased a 2000 'executive' recently and I am most pleased with it. Unfortunately the 'Restricted Performace' light comes on somewhat haphazardly and, also unfortunately, it does exactly that - restrict performance. What is really annoying is that it comes on at any time and then goes off just as haphazardly and pretty quickly. I thought of buying a diagnostic tool to illustrate where the fault lies but the post from the other new member has put me off somewhat. Any suggestions?

 

Not being able to connect is a very rare issue. I have only read of it a couple of times in the past three years, and that was just a blown fuse. You are likely to have a stored code.

 

New reading today lists 12 codes P0301, P0302, P0304, P0308, P1314, P1316, P1642, P0171, P0172, P0174, P0175.

 

Curious about the sequence of events? Did the replacement engine run correctly when you picked it up? Did it idle smoothly? Is the engine now running on only 4 cylinders? Also, when were the plugs, coil (s?), etc changed - when you brought it back?


If it idled correctly and then all this started when you drove it then you should check all of the wiring harnesses that connect to the engine to see if one of them came undone. Maybe a snap connector was broken and a harness has unplugged itself

 

Thanks for your reply and help. All of this happened after the engine was installed. It was running on 4 cylinders when I drove it home. I took it back the next day and he stated the spark plugs, coils, thermostat housing, knock sensors and oxygen sensors needed replacing since the old motor ran hot.

 

considering all those codes, I wonder if they damaged the ECM by either not disconnecting the battery before commencing the engine swap, or by improperly jump starting after.

I expect the battery was dead after sitting for a year, so they had plenty of opportunity to make a serious mistake.

 

Some connector is loose, broken or badly corroded

 

Maybe I missed it in the post, but did you put a brand new battery in? If not- do so.

 

I purchased a new battery today and everything is still the same. I am getting CEL and restricted performance.

 

I think that the OBDII fuse is fuse #4 in the LH heelboard fusebox, not the one in the boot.

Paul

 

That is correct. Also #10 in the RH heelboard.

 

Per the 2000 XJ Vehicle Care Handbook.

Diagnostic connector is fuse #4 in Rear Left Hand Heelboard.

Jaguar Diagnostic System is fuse #10 in Rear Right Hand Heelboard.

You can download the 2000 XJ Vehicle Care Handbook:

https://www.dropbox.com/s/c6y3yn81af...dbook.pdf?dl=0

Jim Lombardi

 

I had a "restricted performance" and CEL light on my '03 XJ8 VDP recently. I pulled the codes and it showed p0172 & p0175 which indicated it was running rich on both banks. That indicated a Mass Air Flow sensor issue. I cleaned the MAF and drove it about 40 miles and the codes cleared on their own. Hasn't come back. The fix took about 10 minutes total time (not including time to go to store and buy MAF cleaning fluid).

 

I had the 'restricted performance problem' generally occur when at a stop . the RPP went off when I pulled away and reached 40 mph.
Upgraded fuel to premium added BK 44 Voila np more RPP.
Now if I can get rid of that pesky low coolant light!!