Supply voltage, low
â–¶ How to fix
1. Check the battery 2. Measure the voltage level between ground and supply.
What you'll see
No driver-visible symptom recorded.
System reaction
When U30 < 22 Volt abscense of heart beat messages will not trigger warnings.
Diagnostic depth
Detection
Supply voltage below 22 Volt. Only stored when ignition is ON.
Possible cause
1. The truck is started in a cool environment 2. Bad conditioned battery 3. The truck is left with ignition on and no engine on for long time, which drains the battery.