BA0842

What BA0842 Means

Code BA0842 comes from the EGS-EME control unit (Electronic Gearbox Control – Electrical Machine Electronics) and indicates the coolant circuit temperature sensor has exceeded its upper threshold. The source lists it among the possible stored fault codes for the hybrid/electric operating modes described.

The temperature sensor monitors coolant heating in the circuit tied to the electric machine and transmission. Exceeding the threshold can point to overheating of hybrid system components, insufficient cooling, or a faulty sensor. The code is stored in fault memory and affects availability of electric driving mode.

Symptoms

• Reduced power in electric driving.
• Electric driving unavailable even with a sufficiently charged high-voltage battery.
• Noticeable engine start on startup; engine start delayed.
• Check Control Message (#2390): “Engine is starting… Please wait.”
• In hybrid mode: reduced acceleration, jerking on upshifts, delays on downshifts.

Diagnosis and Repair

• Report the damage to the dealer now and send photos; otherwise the dealer may later claim the damage was caused by the owner.
• Or live with the dent.
• Or put the license plate frame back on and tighten it firmly.
• A DIY bumper repair won't get a "like new" / presentable result.