IN−38 − INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS Fig. 7 (2) Disconnect connector ”B” and measure the resis- tance between terminal 1 of connector ”A” and body ground, and terminal 1 of connector ”B2” and body ground. Between terminal 1 of connector ”A” and body ground → No continuity Between terminal 1 of connector ”B2” and body ground → Continuity (short) Therefore, it is found out that there is a short circuit between terminal 1 of connector ”B2” and terminal 1 of connector ”C”. 8. CHECK AND REPLACE ECU First check the ECU ground circuit. If it is faulty, repair it.
If it is normal, the ECU could be faulty, so replace the ECU with a nor- mal functioning one and check that the symptoms appear. Sensor 2 1 A B1 C 1 1 2 2 1 2 B2 ECU Z17808 (1) Measure the resistance between the ECU ground terminal and the body ground. Resistance: 1 Ω or less Example Ground IN0383 ECU Side (2) Disconnect the ECU connector, check the ground terminals on the ECU side and the wire harness side for bend and check the contact pressure. Ground W/H Side Ground IN0384 2000 LEXUS LX470 (RM745U) 38 Author : Date: