IN–31 INTRODUCTION – HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS Sensor Side ECU Side IN0379 ECU Side Sensor Side IN0378 1. CONTINUITY CHECK (OPEN CIRCUIT CHECK) (1) Disconnect the connectors at both ECU and sensor sides. (2) Measure the resistance between the applicable terminals of the connectors. Resistance: 1 Ω or less HINT: • Measure the resistance while lightly shaking the wire harness vertically and horizontally. • When tester probes are inserted into a connector, insert the probes from the back. For waterproof connectors in which the probes cannot be inserted from the back, be careful not to bend the terminals when inserting the tester probes. ECU Side Sensor Side IN0380 2. RESISTANCE CHECK (SHORT CIRCUIT CHECK) (1) Disconnect the connectors at both ends. (2) Measure the resistance between the applicable terminals of the connectors and body ground. Be sure to carry out this check on the connectors on both ends. Resistance: 1 MΩ or higher HINT: Measure the resistance while lightly shaking the wire harness vertically and horizontally. Pull Lightly Looseness of Crimping IN0381 3. VISUAL CHECK AND CONTACT PRESSURE CHECK (a) Disconnect the connectors at both ends. (b) Check for rust or foreign material, etc. on the terminals of the connectors. (c) Check crimped portions for looseness or damage and check if the terminals are secured in the lock position. HINT: The terminals should not come out when pulled lightly. Test Male Terminal IN0382 (d) Prepare a test male terminal and insert it in the female terminal, then pull it out. HINT: When the test terminal is pulled out more easily than others, there may be poor contact in that section.