restricted driving mode

[AlistairCampbell]

Following installation of new belt tensioners in my 2000 XKR with circa 50000 miles, when driving home, the car went into `restricted driving mode'.
Struggled back to the garage which undertook the work, they plugged the car into the diagnostics and `no error' was the result, even though the engine was `hunting'. Engine was then switched off and restarted and all seemed ok and able to get back home in normal driving mode. However over subsequent trips, to check if `restricted driving mode' reoccurred, it did but not always, and by switching engine off, locking car and restarting seemed to work for a while.

Car has been off the road over the winter and now have had it out for a couple of 30 - 60 minute runs with no re-occurrence, however still not fully confident to take it out on local JEC runs.

Garage indicated that anything done changing the tensioners would not have caused this problem. In the absence of any diagnostic error code, they also indicated it could be looking for a needle in a haystack.

Anyone else have similar issue and any suggestions where it may be worth checking?

[mike020150]

Going into restricted performance mode after a long lay-off is not unknown. The usual issue is battery related, caused by not having the battery connected to a battery conditioner during periods of inactivity. The drop in voltage may not be sufficient to prevent a car starting but it can play havoc with various of the car's electronically controlled functions. Consequently, if any of this sounds familiar, start by at the least recharging or replacing the battery to see if it could be at fault. Mike.

[AlistairCampbell]

Mike - thanks for the reply, however the car started showing restricted driving mode last May 2017, just after tensioners were replaced. Over the summer the restricted driving mode occurred a number of times. The car was then off the road on a battery conditioner and has been driven a number of times during April but as yet restricted driving mode has not occurred.

[mike020150]

Intermittent faults are always the worst to trace. They take time and inevitably cost money. It's as much a question of eliminating possibilities as anything else. Eg When the car was diagnosed, was it done using generic diagnostics or did the garage use the full Jaguar diagnostics kit or the Autologic Jaguar equipment/software modules (typically used by many Jaguar specialists)? Both the latter can interpret all the specifically Jaguar systems whereas generic equipment cannot and may therefore not read a recorded fault. Mike.