System Test
- Turn ignition on. Locate diagnostic unit and remove its cover. Connect selector cable to socket No. 2. Depress push button 3 times. Each time the button is depressed, it should be held for more than 1 second and less than 3 seconds. While LED flashes, the fuel injectors and idle valve should operate. Check by listening or feeling component when it is activated. If injectors fail to operate and LED flashes, proceed to step 2). If idle valve fails to operate and LED flashes, proceed to step 3).NOTE: Before testing fuel injector circuit on 740 GL, remove auxiliary relay and connect a jumper wire between Blue/Yellow wire terminal and Green/Red wire terminal of relay connector.
- To test fuel injector circuit, connect an ohmmeter between harness side of terminals No. 9 (Orange wire on 240 and 240 DL; Blue/Yellow wire on 740 GL) and No. 18 (Green/White wire on 240 and 240 DL; Gray wire on 740 GL) of fuel system ECU connector. Resistance should be 4 ohms. If reading is greater than 4 ohms, current cannot pass to injectors. See INJECTOR CIRCUIT RESISTANCE table. If resistance is incorrect, remove each injector connector. Each injector connector should have 16 ohms resistance. Repair as required.
- To test idle valve circuit, connect an ohmmeter between terminals No. 33 (Green/Red wire on 240 and 240 DL; Red/Black wire on 740 GL) and No. 9 (Orange wire on 240 and 240 DL; Blue/Yellow wire on 740 GL) of fuel system ECU connector. Resistance should be 8 ohms. If resistance is not within specification, check wiring and connections between idle valve and ECU. If wiring is okay, check idle valve. See IDLE VALVE in SYSTEM/COMP TESTS article.
INJECTOR CIRCUIT RESISTANCE
| Resistance | No. of Faulty Injectors/Wires |
|---|---|
| 5.3 Ohms | 1 Injector/Wire |
| 8 Ohms | 2 Injectors/Wires |
| 16 Ohms | 3 Injectors/Wires |