RESTRICTED PERFORMANCE MYSTERY - ON MOTORWAYS?

[StrayCat]

Seven years on and I'm still in love with my S Type but recently she's been misbehaving.

On longer journeys and, by coincidence always on motorways, the amber engine motif will display with the RESTRICTED PERFORMANCE message. At first there's no feeling that performance is restricted at all until an occasinal cough and splutter makes me pull over and switch off. On restarting, the performance seems restored for a while, despite the warning lights remaining on and I was always able to get home.

Frustratingly, after an overnight rest, the warnings are absent and local driving returns to normal.  It was too easy to put this all down to gremlins and fortunately, in France, motorways were always traffic light. 

However, we're back in the UK and it's happened again, this time in heavy rain and very congested motorway traffic around Manchester. I nursed the car off the motorways and chose a slow and uneventful cross country route to get home. This morning no warning lights are displayed!

I'd appreciate it greatly if anyone has any similar experience or advice which could help me identify the cause of the problem. My local garage has said bring the car in with the warning lights still showing but that never seems to happen.

With sincere thanks in anticipation.

[Old Peter]

Hi Jim,

Have you an OBD2 code reader that will give you a guide.  Your local garage should have one also.

Currently I am doing an IAM Roadsmart course and due to my s type "creeping" a little it was getting occasionally over the speed limit by the odd mile or two.  What I did was to use the manual option and using the J gate I would take it into 3rd gear in urban areas to get some drag.  After a few weeks  "Restricted Performance came up.  The code said "Gearbox Fault".  A much better diagnostic tool than mine more or less told me that the ECU didn't like me going from 3rd gear to Automatic.  Apparently it would have liked me to go from 3rd to 4th and then to 5th before changing to automatic.  I just erased restricted performance and did what I was told to do!

Regards,

Peter.

 

[StrayCat]

Hi Peter,

thanks for your message. I’m a bit ‘old school’ when it comes to fiddling with modern cars so I’ve not invested in a reader as you suggest. For me, I’m sure it would result in a little knowledge being a dangerous thing!

Since posing the question, I’ve learnt of a Jaguar specialist not too far away from where we’re staying so I’ll visit them very soon.

Thanks again.