Hi
I've had my 2009 xf for just over a year. In the last 9 months it started to develop an intermittent fault with an amber dash warning saying both forward alert and dsc was unavailable

The fault code on an obd ii reader was C1b00(1C)

Took it to a local specialist and they advised to replace the steering angle sensor due to the fault code.

That was in August. It seemed to work for a few months after replacement but from October onwards it's been coming back intermittently. Nothing can replicate it, sometimes it's not present for weeks then others is present every day. I'm doing nothing different when it comes on. Sometimes comes on after a few mins, sometimes as I'm about to switch engine off after 30-45 min drive. It doesn't cause any restricted performance and always disappears after a restart.

Fault code same as previous. I've recently changed the battery to see if this helps but still the same random fault every so often.

Does anyone have any suggestions on what it could be?

Cheers
Richard

 

I've not come across this error before but it seems to be an intermittent electrical gremlin.

You've already replaced the sensor and the battery which would be the first port of call, so at a total guess you've got one or more of:

• another faulty sensor (seems unlikely since you've just changed it, but not unheard of)
• fault with the ABS module (I would have thought there would be other errors if this was the case)
• fault in the connection between the sensor and the ABS module
• a ground connection fault

I'm thinking you start with the last two, you could have a slightly poor connection or nicked wire somewhere that is causing a voltage drop or interference so the ABS module is getting the occasional unexpected/no response from one of the position sensors (there's two signals from the one sensor module to the ABS module). The steering angle sensor is critical to the proper functioning of the ABS and DSC and keeping you in control of 2 tonnes of moving metal, if it gets any hint something isn't quite right it will panic.

You could try pulling and cleaning the connectors on the sensor and ABS module, and measure the resistance between the ends (make sure the ABS module and sensor are not connected) as well as to ground. It should be almost 0, see if it changes if you wiggle the wires to see if there something is loose or broken in them.

 

Thanks for the advice

Will have a look this weekend at the connectors and check for any signs of corrosion and see if it's any better after cleaning. Happened again this morning but nothing on the drive back from work

 

You might need a better scan to narrow down what module its not able to communicate with. Then check physical connections, then reflash, then replace if it still persists.

My 2009 trips these errors but only every few months, either right at startup or even after using cruise but fails on resume.

My guess is the radar, which is a sensitive instrument converting the digital to analog, but mounted low exposed to the elements, and right by the heat of the radiator, so it might be time. And it goes with how after 10 years/100k miles, just replace everything. If mine ever gets bad I will just code it out with SDD and move on. These first gen ACCC systems were mediocre to begin with.

 

Thanks.

I've just checked the acc radar at the front. Connections seemed ok, all shiny pins but I've got a feeling it might be the radar itself as it seems to have been replaced in the past already. A previous owner has cut out some of the plastic mesh in front in order to get to it easily and the current radar is from a range rover sport (must be from salvage yard)

I've ordered a new code reader and software to see if I can disable the ACC as I never use it. Not sure how easy it is but will scan first to see if I can get any more information. Like you said if it's a drop in voltage arising from a faulty radar then that might be the source.