Network, generic (extended)
U3542 High Voltage System Interlock Circuit O Performance
Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modePossible
U3542 marks loop O as implausible. Interlock trouble often clusters around charging. Mercedes bulletin LI54.10-P-067823 for the third-generation smart electric drive with the optional 22 kW on-board charger, built before 25 March 2013, links sporadic or permanent interlock codes (P0A0A00, P0A0E00), a no-start with a charging-cable message and a battery that will not charge to loose low-voltage contacts at that charger. Technicians push or pull those plugs gently and wait up to 5 seconds each time to see whether charging begins; the fault may appear solely with cold or warm components. No maker documents U3542.
Likely causes
Loose low-voltage contact at the on-board charger carrying loop O
Contact that opens only when components are hot or cold
Internal fault in the on-board charger
Symptoms
- Vehicle will not start and reports a plugged-in charging cable
- Charging does not start or stops
- Fault at the beginning or end of a charging session
Repair estimate
DifficultyHardWorkshop job
Parts and labour€50–2,500
Time0.5–4 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
hvil loop oon board charger
Related codes
References: static.nhtsa.gov, law.cornell.edu.