Richard Hinds
Senior Member
My 2016 SL400, 17,000 miles, is playing up big time!
On initial start-up, everything will function fine. Then after about 20 minutes, the yellow engine management light will come on, and weird things happen. The "C" for Comfort light disappears, the light showing "stop start" is available disappears, the "D +a number" (showing which gear the auto box has selected) disappears, then there is a "bong" followed by a red light script "without changing gear, visit workshop". The Fuel gauge will flicker, the needle drops to zero. Then things will return to normal, and then it happened again. Each time I've managed to reach my destination, although very occasionally the engine has "Coughed".
The car has been booked into a Mercedes specialist. They read the various fault codes, and said various modules are not talking to each other, because the battery volts are too low.
As the battery was now about 7 years old, I accepted the battery may be past its best, and so installed a new one. The faults persist!
I am reluctant to pay for each and every module to be replaced, one at a time, and at great expense. I also understand intermittent faults can be very difficult to track down. Due to the behaviour of the fuel gauge, I suspect an intermittent wiring fault, or possible rodent damage.
Has anyone any sensible solutions to offer?
Thanks in advance, Richard
On initial start-up, everything will function fine. Then after about 20 minutes, the yellow engine management light will come on, and weird things happen. The "C" for Comfort light disappears, the light showing "stop start" is available disappears, the "D +a number" (showing which gear the auto box has selected) disappears, then there is a "bong" followed by a red light script "without changing gear, visit workshop". The Fuel gauge will flicker, the needle drops to zero. Then things will return to normal, and then it happened again. Each time I've managed to reach my destination, although very occasionally the engine has "Coughed".
The car has been booked into a Mercedes specialist. They read the various fault codes, and said various modules are not talking to each other, because the battery volts are too low.
As the battery was now about 7 years old, I accepted the battery may be past its best, and so installed a new one. The faults persist!
I am reluctant to pay for each and every module to be replaced, one at a time, and at great expense. I also understand intermittent faults can be very difficult to track down. Due to the behaviour of the fuel gauge, I suspect an intermittent wiring fault, or possible rodent damage.
Has anyone any sensible solutions to offer?
Thanks in advance, Richard
