My SL350 will not start

[andywebb]

Hi has anyone in the Kenilworth (Warwickshire) UK area got a fault reader they could link to my 2008 SL350?
I linked the CTEK charger to my boot battery ready for winter and that was the last time it started. Fitted a new battery and tested engine battery all appears good. Tested every fuse I can find inc footwell ones but still no joy. Tested relays appear ok.
Ignition comes on all gauges light up but when you push button or turn key to start nothing other than fuel pump noises etc.

 

[MikeInWimbledon]

(Some dumb questions like this might get you to the solution quicker than electronic diagnostics plug.)


So exactly has happened? Have you used the car recently?

When and why did you change the battery, and which battery did you change? (I assume you changed the consumer but can't take that for granted)

Did you replace the battery because the car already wasn't starting with the old battery?

Did you change the battery or did someone fit it for you? Did it start after it was fitted?

(Apologies for asking but) Are you certain that the connectors to the battery are solid and correct, with no corrosion undermining the connection?

 

[andywebb]

Car working fine with winter approaching thought I would get a trickle charger so got Ctek device .
Connected and it’s lights indicated it needed a charge so let it run its course.
When completed disconnect Ctek now car will not start.
Purchased new battery for the boot still no change.
Tried Noco battery booster on both battery’s still no start.
Charged both battery’s although they both indicated they didn’t need any charge still no start.
Went through fuse boxes and tested relays remove passenger carpet to test fuses in footwell

 

[andywebb]

Ctek was connected to the boot battery as that what people say need’s maintaining over the winter

 

[Jobsworth]

The battery under the bonnet just does the starter motor. Everything else runs from the rear battery. Have another look at the battery in the front

 

[andywebb]

In all the time I have owned the car I have never had it not start I don’t think there was anything wrong with the boot battery just changed it out of desperation and to eliminate it.
Booster is a good one so if the battery’s had any issue I thought using that would eliminate it.

 

[alabbasi]

Did you check the front battery? We don't have the 350 here but I assume that all R230s have a starter battery under the bonnet

 

[andywebb]

Yes it is a R230 and yes i have tested starter battery

 

[whitenemesis]

As others have said check/charge the under-bonnet battery. You said the IGN came on and all the gauges lit up, so the consumer battery in the boot would appear fine.
Just remember if disconnecting the engine bay battery you must disconnect the negative from the boot battery first and reattach said neg after reconnecting the front battery. You don't need to disconnect to recharge the battery, just connect directly to the battery terminals

From the WIS training doc..

Removal/installation
Starter battery (G1/4)
Procedure for removing the starter battery (G1/4):
• Switch off ignition and switch off all electrical
consumers.
• Remove transmitter key (A8/1) from EIS [EZS]
control unit (N73).
• Disconnect ground line of on-board electrical
system battery (G1) and protect it against uninten￾tional contact.
• Disconnect ground line of starter battery (G1/4)
and protect it against unintentional contact.
• Disconnect positive line of starter battery (G1/4).
• Remove starter battery (G1/4).
After removal/installation of the starter battery
(G1/4) basic programming (normalization) of the
vehicle is required.

 

[MikeInWimbledon]

Ctek was connected to the boot battery as that what people say need’s maintaining over the winter

They are right, the boot battery is the one that goes flat if you don't use the car for a month.

But.... the boot battery is deliberately all the things "you don't need."

Its the battery in the front that starts the car.

If the boot battery was low you'd get an error message on the central console, and you'd lose the ability to open and close the roof, or run the radio.

See white nemesis' note on the connection protocol after changing a battery.