I have a Jaguar XF 2.2 Diesel, owned for the last 3 years and a beautiful motor that i've looked after on an almost religious basis.

In the last few months we've had the bad weather from the 'Beast from the East', bringing the snow and all the problems along with it. The jag handled it well, but since then, i've had a 'Restricted Performance' warning light coming on.

I've taken it in for a service and they came back with some codes but the garage said that most of them were old codes, and the existing ones were cleared and not shown up since. I drove it home and after a while the light came back on again.

I did some research and a few sites have said that it's down the turbo intercooler - this is one of the things i asked the garage to look out for, and he gave me a list of the fault codes and this doesn't show up.

Does anyone have any ideas what else could be causing it? I have noticed that there's a slight "whoosh" from the left side of the engine when i go up to 50 (like joining the motorway etc.), but if the garage didn't find it i'm at a loss at what else it could be?

 

Can you reset the codes, drive for a while then pull the codes and post them here? Hard to assess without the specific codes.

 

Cheers, any help would be appreciated - the codes were cleared when i had the service, and i checked with my OBD device today and it's showing no fault codes, even though it came up with the error message when i drove it back home yesterday.

A lot of the codes were relating to old changes - e.g. changed the battery in my key fob when it ran out, brake pads changed, so they cleared everything, saying bring it in or speak to a Jag dealer if the message shows up again. This is the list of codes that the garage gave me;

Instrumentation
C004A - Brake Pad wear sensor (Open circuit/B+ short)
B100A - Electric fuel pump monitoring (Missing message)
B100D - Electronic steering column lock (Signal plausibility not OK)
B100D - Electronic steering column lock (Internal fault)
B1B01 - Transponder key (Malfunction)
B1B01 - Transponder key (Configuration error)
B1B01 - Transponder key (Incorrect/no signal)
U0199 - Communication with door control unit A (Malfunction)
U0200 - Communication with door control unit B (Malfunction)
U2010 - Button illumination (Open circuit/B+ short)

Convenience 1
Access/start authorization
U0140 - Communication with Body Control Module (Malfunction)
U0142 - Communication with Body Control Module B (Malfunction)
U2101 - Control Unit configuration (Malfunction)

Driver info 1
Info display
U0142 - Communication with Body Control Module B (Malfunction)
Audio
B1A56 - Antenna
Gear Control
P0942 - Automatic transmission servo module (Signal compare faulty)

Central Electronics System
B10AD - Rain Sensor (Component Faulty)
B12A6 - Supplementary/auxiliary heater additional water pump (Open circuit/B+ short)
B13CE - Unknown fault
B1C79 - Windshield washer pump relay (Short to ground)
B1C79 - Windshield washer pump relay (Open circuit/B+short)
U0142 - Communication with Body Control Module B (Malfunction)
U0155 - Communication with instrument cluster (Malfunction)
U0164 - CAN communication with air control unit (Malfunction)
B1B01 - Transponder Key (Missing message)
B1B33 - Transferred key code (Signal plausability not OK)
U0199 - Communication with door control unit A (Malfunction)

Electr.select.lever module
U0415 - CAN signal from ABS (Faulty operation)

Airbag
B11A1 - Unknown Fault

Parking brake 2
U0415 - CAN signal from ABS (Malfunction)

 

You do seem to have quite a few communication DTC's logged. It is common to get a few on a normal basis.


Just for grins, have you checked the battery, make sure its up to par.


As for your P0942 code -this relates to internal transmission failure. New vehicles will have a 7 digit code instead of the 5 digit one you've posted. You " might " be able to get away with a software update, but its worth a try.


You'll need to have the codes cleared, drive it, and see what comes back. I do see you have a code there for the brake pad wear sensor, have you fixed this??


See attached

 

Yes, I got the brake pads and calipers replaced during the service (brake pads for life, replaced even if I change cars!)

I've run it for a couple of days now and used the Torque OBD, the only code it brings up is P006A, which is a MAF sensor fault? The engine light came on and I checked the OBD and it still shows the same fault code. I don't know whether to replace the MAF or just give it a clean and try again.

 

I had the same experience the last week or two. For about a month there was a hissing noise on acceleration with no RP message. One morning when I had to drive over the mountain, PR lit up. I was able to keep going, but very slow over the mountain. On a level road, no problem to reach a decent speed if you use the manual gear change, but on a slight incline, no power at all.

To test for a cracked inlet manifold is also apparently quite simple. Detach the MAFS housing from the air intake. Block the air intake while the engine is running with your hand. If the engine stalls and the vacuum stays strong for longer than a minute, there is not much wrong with the manifold. If it was cracked, there would either not be much of a vacuum, or it will disappear in a few seconds after the engine stalled.

Seems that the MAF sensor is the problem. On another forum a user said it is easy to test the function of the MAF sensor:
Start the car, open the bonnet, and detach the MAFS connector. If the engine stalls, MAFS is functioning well. If the engine keeps going, MAFS is the culprit and needs replacement. I bought a MAFS on ebay, $29 for the MAFS and $28 for shipping to South Africa. Hopefully it will arrive by end of next week.

I will post again if it solved my problem.

Cheers, Wiekus

 

Mostly a hiss is a HUGE air leak.

Even a tiny one would need fixing.