Heater plug checking method for internal combustion engine, involves using comparison result of voltage drops measured at path bounded shunts and at common shunt to draw conclusion about faulty heater plug

摘要

The method involves connecting two heater plug paths (P1, P2) on a common shunt (SC), where the heater plug paths run over path bounded shunts (S1, S2). A voltage drop is measured at the common shunt and a voltage drop is measured at the path bounded shunts. The voltage drops are which are compared with each other. Comparison result is used to draw conclusion about faulty heater plugs (GP1, GP2). The faulty heater plugs are closed in the heater plug paths in which each unmeasured shunt is provided, in case of an equal voltage drop. An independent claim is also included for an electrical circuit for examining heater plugs in an internal combustion engine.