Test Main relay (K1) Flash code: 2x long, 5x short Fault indication: Fault is not indicated by EDC indicator lamp Fault path: Main relay Contact sticks or jams (does not open) Effect of fault: Under certain conditions this fault may not be detected Function: The negative pole of the main relay is addressed by the EDC con- trol unit through the control unit output pin 46. The main relay K1 switch off is delayed after the “ignition” is switched off (afterrun- ning). Green LED goes out. During the afterrunning phase, various processor functions are checked and any faults stored in the fault code memory Possible cause Short to ground, main relay K1 defective Test precondition:
EDC control unit disconnected / connected Socket box connected Note: Pin 46 must switch to U-Batt with a delay of up to 5 seconds after turning off the “ignition” (processor afterrunning). 54 Test Measurement Corrective measures Main relay Measure voltage at socket box across pin 47 and pin 18 Setpoints: 0 V at “ignition” off U-Batt at “ignition” on Measure voltage at socket box across pin 46 and pin 18 Setpoints: U-Batt at “ignition” off 0 V at “ignition” on – Check lines – Check plug connections – If line OK, replace main K1 relay If U-Batt is not present when “ignition is on” – check relays K2 and K3