Today I had a restricted performance message, but no code logged that I could see with my reader. I can see pending codes but did not even get one of these.

This went away when I turned the engine off. The restriction type was throttle %ge. I.e. I have had restricted performance before with misfires, these limit the revs but the throttle response is still there.

I have high fuel trims (particularly on one side) and a known air leak (just can't see where it is!), but these would log a code on any error I can think of.

I have also had a very occasional (as in twice) high gearbox temperature code while the car wasn't even warm, so I have to look at the connector there. Other than that I have no problems I know about.

Any ideas what can cause restricted performance without logging an OBD code? Or one that a generic code reader can't see?

 

Mike,
I had a Voltage Regulator go bad a while back.
It's located in the Alternator itself.
It created an overcharging situation (17 plus Volts).
I got the "Restricted Performance" message until I replaced the Alternator and got the voltage back down to about 14 volts.
You may want to check the charging system for over-charging.
Dave B.

 

Thanks for the suggestion Dave,

did/should that show up on the dash voltmeter? I haven't noticed mine being high

 

Mike,
Check your aux. intercooler pump fuse. It's located in the engine compartment next to the firewall on the passenger side on my '06---not sure if it's the same on your MY. I had a failed pump on mine and would get the RP light only when pushing the supercharger hard, like climbing hills at freeway speeds. Good Luck. There's also a discussion of this in the XKR FAQ section.

 

Plug your code reader in and take the car for a run the reader should capture the code when the restricted performance comes up.

 

I had a code reader in at the time - well that is to say I plugged it in when restricted performance came up.
No freeze frame data either which I expected.
Makes me wonder if it's another system that obd can't read which is throwing a code?

 

It will only set a code if it reoccurs two times in a given time period so your fault is of a temporary nature. Plug the reader in and drive the car I use a $29.95 OBD reader and it captures temporary faults all the time for me.

 

you're absolutely correct gus! On the way home I got an actual code, back to my misfire on 7 & 8 for a couple of minutes after start.
New coils, swapped plugs with 5&6, still this. Wiring or injectors I suppose. I know I have a vacuum leak, still chasing the exact location (when smoke testing I see smoke from between charge cooler and blower outlet, can't see the exact starting point) could this cause this problem on specific cylinders?

 

I am not sure it would. I would suggest you add BG 44K to your gas and drive the car if it is an injector the BG fluid will clear any sludge unless you have a bad injector. I would give this a try first! You can get the BG 44K from any good repair shop or any dealership.

 

thanks - been there & done that unfortunately. anything else I can do with the blower still on?

 

Take the ducts out between the intercoolers and take them apart, clean and run a bead of silicone between the sealing flaps and reinstall before it dries. I do this even on new ones as they till can leak

 

sorry - not sure if I was clear with my description of the leak location. I see smoke rising but can't see where it originates, it comes up between the charge cooler and the outlet manifold. Could be the partial load breather, or something down in that area that I can't make out (I have a borescope on the way)

If I understand you correctly you are talking about the rubber seals between the outlet manifold and charge/intercooler - these are fine