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Diagnosis & Repair (Using 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.
  1. Connect hand-held tester to Data Link Connector (DLC) No. 3. See Figure. Using hand-held tester, select ACTIVE TEST mode. Select VVT. Note idle speed when Variable Valve Timing (VVT) Oil Control Valve (OCV) is activated by hand-held tester. If idle speed does not function as specified, go to next step. If idle speed is normal with VVT OCV off, and engine idles rough or stalls when VVT OCV is on, VVT is functioning properly at this time. DTC may have been set because of a foreign object that was temporarily caught in engine oil system but after a short time system returned to normal.
  2. Start engine and allow it to idle. Disconnect VVT OCV harness connector and note idle speed. OCV is located in cylinder head, at timing chain side of engine. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV terminals. 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.
  3. Turn ignition off. Connect VVT OCV harness connector. Access ECM behind glove box. See Figure. Using oscilloscope, backprobe ECM harness connector and connect oscilloscope between terminals No. 19 (Green/White wire) and No. 29 (Yellow/red 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.
  4. 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.
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