Diagnosis & Repair (Without Toyota Hand-Held Tester)
WARNING: This page is about a different car, the 2002 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
- Start engine and allow it to idle. Disconnect Variable Valve Timing (VVT) Oil Control Valve (OCV) harness connector and note idle speed. VVT OCV is located is mounted on intake side of cylinder head, on flywheel side of engine. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV. Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV.
- Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. See Figure. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. See Figure. Using oscilloscope, backprobe ECM harness connector. For bank No. 1, connect oscilloscope between terminals No. 5 (Green/Yellow wire) and No. 6 (White/Green wire) at ECM harness connector E9. For bank No. 2, connect oscilloscope between terminals No. 18 (Yellow/Red wire) and No. 29 (Green/White wire) at ECM harness connector E9. See Figure. Start engine and let idle. Ensure oscilloscope pattern is as shown in illustration. See Figure. As engine speed is increased, waveform frequency ("A") should lengthen. If waveform pattern is as shown, go to next step. If waveform pattern is not as shown, replace ECM.
- Check for an open or short in wiring between VVT OCV and ECM. If problem exists, repair wiring as necessary. If problem does not exist, problem is intermittent. Check component and ECM connections.