My Jag 2.7 S Diesel battery drain down recently. I replaced the battery but now I'm experiencing "restricted performance mode" on hard acceleration which never happened before.

 

Welcome to the forum vanwyck,

I've moved your question from General Tech Help to S-Type forum. Members here with the same model will be able to help.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Really not a lot of experience with the diesel S-type in North America. However, the UK seems full of problems just like yours, but I have not seen a posting saying "It's fixed", other than when Jaguar replaced the turbos.

From all the descriptions, the problem shows up under hard acceleration and seems to disappear (temporarily) after the engine is allowed to cool down. So, it seems that the turbos are over-heating and, under Restricted Performance, are being disabled for their own protection.

Just for the record, I got Restricted Performance one day under hard acceleration on my 2005 STR. It was a complete surprise, but everything that followed was identical to the diesel experiences.

Yes, the problem was over-heating of the supercharger, which the ECU shut down for protection. The culprit was the electrical auxiliary pump that supplied coolant to the supercharger - no coolant = overheated supercharger = Restricted Performance. Replaced the pump (not cheap), no more problem.

I have no idea whether the STR and Diesel Sport have much in common to do with supercharger/turbo cooling, but any reply may be of help here.