Starting/Ignition Issue - EML Code U0121 - No Car Play

[dobber82]

Okay, so last few days I have this scenario....

1. Unlock car and keep door open
2. Single Press the seat memory to get into my position
3. Try to start but it wont
4. Lock car
5. Unlock car
6. It starts

I have had this and when this happens it throws the ABS U0121 code and car play doesnt work. Drive, stop, start and all good and car play etc works.

I never knew you could do point 2 until a week ago and since I have been doing this I have had this issue. Anyone else had this under this "scenario" ... I am going to stop doing point 2 and see if it stops happening.

 

[dobber82]

Ok so drove twice today without point 2 and had no issues ...

 

[scc.131.fe]

Ok so drove twice today without point 2 and had no issues ...

my only guess is that point 2 has a more substantial power consumption from the battery than the electronics waking up. if your battery is marginal, moving the seat may be causing a voltage drop below threshold for the ABS module and/or other gizmos.

As a habit, when I park the car I press memory 1 to back the seat way up while the engine is still running for my egress/ingress. next drive, when I get in, I leave the seat at 1 until I start the car, then use 2 for my driving position. With a healthy battery this should not matter, but I like to generate habits that make it easy on a battery, especially for a car that wakes up so much stuff just by unlocking and opening the door.

if you are handy with an oscope or multimeter that has a "min" voltage capture, you could read battery voltage while moving the seat with the engine off and see how low she goes....