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Richard, Jaguar Technician
Category: Jaguar
Satisfied Customers: 15555
Experience:  12 years at a Ford/Lincoln Mercury and Jaguar dealer as technician and shop foreman.
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I had a "restricted performance" message come on yesterday

Customer Question

I had a "restricted performance" message come on yesterday on my 2001 XK8 while idling for a few minutes in a parking lot. Turned the engine off, and when I turned it back on, it ran normally. This happened twice within 10 minutes. What does this message mean, and is it something that I need to get checked out immediately? Thanks for your help.
JA: How many miles are on the car? What size is the engine?
Customer: Approximately 53000. V8.
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Nothing yet. It seems to be running normally now, but I'm worried about sudden problems on the road.
JA: Anything else you think the mechanic should know?
Customer: That's about all I know at this time. It did start to run rough when it happened, but ran fine after turning off and back on.
Submitted: 1 year ago.
Category: Jaguar
Expert:  Richard replied 1 year ago.
When the restricted performance warning comes on the engine control module has detect a fault effecting the performance and or emissions of the engine. Since it reset after an ignition cycle this is most likely electrical like one of the sensors. For example a faulty mass air flow sensor or ignition coil can be the cause. I also have seen vacuum.leaks from a cracked breather or vacuum hose cause this. to be sure we will need to have the vehicle scanned for the stored fault codes. A Jag compatible tool will be needed to do this. I recommend you go to your local parts store to see if they have a generic OBD II scan tool you can use to pull the fault codes. It will read as a P followed by four digits like P0171. I don't recommend we disconnect anything until we can get the fault code. We can do a visual inspection of the breather and air intake tubes for looseness in damage. Let me know.
Customer: replied 1 year ago.
Thanks Richard. I will get the codes as soon as possible, and let you know what I find.
Expert:  Richard replied 1 year ago.

Sounds good. Let me know.

Customer: replied 1 year ago.
Attempted to get codes, but the reader wouldn't give me anything because it says that the sequence won't finish. This happened before, and I had to take it to the Jag dealership to fix. Thought it was corrected, but looks like it has happened again. Not happy about this.
Customer: replied 1 year ago.
I was able to get a code finally - P0355, Ignition coil Primary/Secondary circuit. It happened again today as I was driving around and stopped at a light. It went away after a few seconds, and ran fine all the way home. Can you give me an idea of what to do next?
Expert:  Richard replied 1 year ago.
Ok great. We need to check the cylinder 5 ignition coil as it may be faulty. Cylinder 5 is the front cylinder on the passenger side. Remove the six coil cover screws then the two bolts on the coil
Customer: replied 1 year ago.
I appreciate your assistance, but I'm not able to do any of the engine work. I would really appreciate your guidance with what to tell the folks at the Jag dealership when I take it in next week. My experience is very limited with engines, and I wouldn't want to screw things up any worse than they are. Is there anything specific that I should tell them?
Expert:  Richard replied 1 year ago.

I suspect the coil will need to be replaced. We also need to confirm that no oil is leaking into the coils. Keep me posted.