Hi All,
Firstly thank you to everyone on here as I wouldn't be this far on without many of the threads on here.

So the stop start on my 2013 XF has worked once since I bought the car six months ago. It's not a biggee as I'm working from home / not commuting at the moment (for obvious reasons). However its one of these things that is niggling at me.

I have; changed both batteries, reset the BMS, reset the ECU learned parameters, and re-calibrated the throttle position. After all of this I have now got to a position where the car runs and shifts a lot nicer and the PCM isn't inhibiting the stop start for any reason I can see. I've uploaded a readout of a short drive cycle so you can see the parameters I've been watching for diagnostics with my iCarsoft CR. Theses are the only ones I can see that are relevant to the SS functionality listed in the PCM. However SS still ins't kicking in.

The only thing that read oddly to me is that the "Transmission control module economy stop/start request status" says "----- No request" at rest, but I don't know if that's normal... I cant see anything in the TCM parameters that talks about stop start, but I might have missed something. Are there any other places to look w.r.t. stop start inhibition?

Anyway, does anyone have any ideas? Any constructive feedback would be much appreciated.

Cheer
Barry M

 

Barry,

Technical questions are best posted in the MODEL forum. The REGION forum is aimed at geographically relevant posts such as meetings.

As I recall from when I was considering an F-Type with the same intelligent stop/start system, if the dual battery system can't prevent electrical supplies to the vehicle systems being subjected to low voltage levels during engine stop/start operations (due to the condition of the primary and/or secondary batteries or a system fault) the stop/start feature is disabled.

The first and most obvious cause of the problem is partially dicharged or failing batteries but you have (almost) negated this with replacement. Did you fully charge both batteries before fitting them? New batteries need a charge when coming from a supplier to avoid problems. Infrequent use is likely to contribute to difficulties here and a CTEK or similar would be essential.

The next suspect would be the GWM (Gateway Module) which controls the charging system software, monitors the status of the stop/start system and determines when a stop/start event can occur. A fault here could disable stop/start. I see from the Parts catalogue there's also a DBM (Dual Battery Module) and a DBJB (Dual Battery Junction Box) on the dual battery models which give further possible causes for either component or harness.

I'm not familiar with iCarsoft CR and my choice would be Jaguar SDD to look for relevant DTC's. The dual battery stop/start system seems fiendishly complicated just from the components and a Workshop Manual is likely to be essential as a troubleshooting tool. As you are probably aware, these are all online through TOPIx for later models.

Graham

 

Barry, the first question you must ask yourself is do you really really want the stop-start system to work? Because it achieves the square root of stuff all.
On my F-Type it was a right royal PITA from day one, totally unsuited to such a car and I suggest also totally unsuited to an XFR.
Before the F-Type I had a 2010 XFR that didn't have stop-start.
So the first thing I did on my F-Type when I got it home was to permanently disable the stop-start system.
My F-Type has (had) a dual battery system just like your XFR, and all it took to disable the stop-start was to disconnect the earth lead from the secondary battery from where it bolts to the floor of the boot/trunk. It runs from the negative terminal of the secondary battery.
I did this nearly four years ago, then completely removed the secondary battery some six months ago, and I have never had a single problem, it simply permanently disables the stop-start system with zero side effects.

 

The same thought did cross my mind.

However, this is a symptom of something fundamentally wrong. The concern has to be the vehicle could go from the present no STOP/START scenario to just a STOP scenario.

Graham