Back to the topic, does anyone have a chart that shows all the symptoms that trigger Restricted Performance? Most symptoms are triggered in some sort of sequence to then be grouped under the "Restricted Performance" category, so there must be a completely logical flow of conditions - taxonomy of events that will then display the message "Restricted Performance" with or without a MIL DTC code.

I have seen in all four my Jaguars since 1996 an issue of Restricted performance coming on after a fuel fill up, then typically goes off after 20 miles. I will venture a guess that the ECM programming is through one source for JLR since Ford ownership across at least 4 or 5 model changes - meaning the same idiot algorithm has been used without modification for 15 or more years.

I have also seen Bank A or B too lean or Bank 1 or 2 too lean conditions trigger Restricted Performance everything from vacuum leaks and misfires, along with defective knock sensors, defective MAS sensors, defective O2 up and downstream sensors, defective coolant temperature sensors, and of course issues triggered from transmission faults.

Point is, you have to get a feel of what is going on leading up to when the Restricted Performance is being triggered along with other potential DTC's. It could originate from many areas.

 

Hi StagByTriumph,

The document I know of that comes closest to providing a list of faults that can trigger RP is the DTC Summaries manual. It does not state that a certain fault will trigger RP, but under the Default Action column in it does state when a fault will take an action that is often directly related to Restricted Performance, such as "Maximum engine speed reduced," "Mechanical limp home mode," "Electronic limp home mode," etc.

Here's a link to one of the most complete versions of the manual:

Jaguar X350 DTC Summaries 2004 Onward

The ECMs and engine management systems have changed over the years, from Lucas/Bosch (XJ40 and earlier) to Lucas/Sagem (X300), to Denso 16-bit (X308) and Denso 32-bit (X350). But you're right that many of the same faults have had the capacity to trigger RP in all of those EMSs.

Cheers,

Don