HEATED OXYGEN SENSOR OPERATION
If circuit or component is faulty, a Diagnostic Trouble Code (DTC) should set. Retrieve DTCs and perform appropriate diagnostic test. See appropriate SELF-DIAGNOSTICS article.
Fuel Injector Operation
Remove engine cover. Using a stethoscope, listen for clicking from each injector (or feel injector for vibration using a screwdriver) with engine running or cranking. If clicking is not heard, check for loose connection at fuel injector connector or fuel injector resistance. See FUEL INJECTOR RESISTANCE. If fuel injector is okay, check for no voltage signal at suspect injector connector.
SYSTEM OPERATION
Note. For information on engine immobilizer, see THEORY & OPERATION article.
| CAUTION | If ECM replacement is instructed during any test procedures, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES - LEXUS article in GENERAL INFORMATION. |
- Ensure engine is at normal operating temperature. Ensure idle speed is 650-750 RPM. Ensure transmission is in Neutral. Turn A/C off. Connect Fused Jumper Wire (09843-18020) between terminals TE1 and E1 of DLC No. 1. (Scheme 187) On ES300, DLC No. 1 is located on front of air intake chamber. On RX300, DLC No. 1 is located on left side of engine compartment, behind fuse box.
- On all models, engine speed should increase to about 1000 RPM for about 5 seconds then return to idle (650-750 RPM). If engine speed is as specified, go to «AIR ASSIST SYSTEM»(ref-151786-S09426590902003010800000). If engine speed is not as specified, disconnect jumper wire from DLC No. 1. Check IAC valve operation. See «IAC VALVE OPERATION»(ref-151786-S28003669062003010800000). Replace IAC valve as necessary. If IAC valve is okay, check for open or short in IAC valve wiring. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. Repair wiring as necessary. If wiring is okay, replace ECM.
Scheme 187
IAC VALVE OPERATION
Remove throttle body. Remove IAC valve from throttle body. Check IAC valve position. IAC valve should be in half open position. (Scheme 188) Connect IAC valve connector to IAC valve. Turn ignition on and observe IAC valve operation. IAC valve should move to fully closed, fully open and then to half open position within.5 seconds of turning ignition on. If IAC valve operation is not as specified, replace IAC valve and retest.
Scheme 188
VARIABLE VALVE TIMING (VVT) SYSTEM OPERATION
If VVT system circuits or components are faulty, a Diagnostic Trouble Code (DTC) should set. Retrieve DTCs and perform appropriate diagnostic test. See appropriate SELF-DIAGNOSTICS article.
Oil Control Valve Operation
Remove Oil Control Valve (OCV) to be tested. Connect a fused jumper wire between battery voltage and terminal No. 1 at OCV. (Scheme 189) Connect another jumper wire between negative battery terminal and terminal No. 2 at OCV and note OCV plunger operation. With battery voltage applied, plunger on end of OCV should extend. Disconnect a jumper wire. Without battery voltage applied, plunger should retract. If OCV operation is not as specified, replace OCV.
