IN−36 − INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS (d) Prepare a test male terminal and insert it in the female ter- minal, then pull it out. NOTICE: When testing a gold−plated female terminal, always use a gold−plated male terminal. HINT: When the test terminal is pulled out more easily than others, there may be poor contact in that section. Fig. 1 6. CHECK OPEN CIRCUIT For the open circuit in the wire harness in Fig. 1, perform ”(a) Continuity Check” or ”(b) Voltage Check” to locate the section. ECU Sensor 2 2 2 1 1 1 1 A B C OPEN 2 Z17004 (a) Check the continuity. (1) Disconnect connectors ”A” and ”C” and measure the resistance between them. In the case of Fig.
2, Between terminal 1 of connector ”A” and terminal 1 of connector ”C” → No continuity (open) Between terminal 2 of connector ”A” and terminal 2 of connector ”C” → Continuity Therefore, it is found out that there is an open circuit between terminal 1 of connector ”A” and terminal 1 of connector ”C”. (2) Disconnect connector ”B” and measure the resis- tance between the connectors. In the case of Fig.
3, Between terminal 1 of connector ”A” and terminal 1 of connector ”B1” → Continuity Between terminal 1 of connector ”B2” and terminal 1 of connector ”C” → No continuity (open) Therefore, it is found out that there is an open circuit between terminal 1 of connector ”B2” and terminal 1 of connector ”C”. Fig. 2 ECU Sensor 2 1 A B C 1 1 2 2 Z17005 Fig. 3 ECU Sensor 2 1 A B1 C 1 1 2 2 1 2 B2 B04722 2000 LEXUS LX470 (RM745U) 36 Author : Date: