U3545High Voltage System Interlock Circuit P
- Generic OBD-II code · Network
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- U3545 is the general fault code for interlock circuit P, the fifteenth loop. Interlock electronics can be harmed by events elsewhere in the drive. Allison service letter SIL 3-EP-14 (Rev. C, 2017) for the H 40/50 EP hybrid system used in buses offers a separate HVIL circuit card for the DPIM2 inverter: if the check list shows 3 to 4 µF between DC+ or DC− and chassis, for example after an internal stator short, that card is damaged and can be swapped instead of the whole inverter, which first has to come out of the vehicle; an ESD wrist strap is mandatory. No maker documents U3545.
- What you may notice
- Vehicle cannot be made ready
- Other drive faults stored at the same time, such as motor or isolation faults
- Likely causes
- PossibleInterlock circuit board inside the inverter damaged, e.g. after a motor winding short
- PossibleConnector in loop P not fully latched
- PossibleLoop P wiring damaged
- RareElectrostatic damage to monitoring electronics during service
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €300 – €8,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.