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Diagnosis & Repair (Using Lexus Scan Tool)

WARNING: This page is about a different car, the 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check valve timing. See appropriate article in ENGINES. Repair as necessary. If valve timing is okay, go to next step.
  2. Start and run engine. Allow engine to reach normal operating temperature. Connect Lexus scan tool to Data Link Connector (DLC) No. 3. See Figure. Select VVT from scan tool ACTIVE TEST menu. Using scan tool, turn OCV on and off. If idle speed is normal with OCV off and engine idles rough or stalls when 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. If idle speed does not function as specified, go to next step.
  3. Access ECM at left front of engine compartment. Backprobe ECM E2 connector. Start engine. Using oscilloscope, check waveform pattern between terminals No. 5 (Yellow/Black wire) and No. 6 (Red/Yellow wire) at ECM E2 connector. See Figure. Slowly increase engine speed. Waveform frequency "A" should lengthen as engine speed increases. See Figure. If readings are not as specified, replace ECM and retest. If readings are as specified, go to next step.
  4. Remove timing belt cover and timing belt. See appropriate article in ENGINES. Remove OCV. Place a shop towel under OCV cylinder head opening. Rotate VVT pulley from left to right about 30 degrees 2-3 times. Oil should drain from OCV cylinder head opening. If oil does not drain from opening, replace VVT pulley/gear assembly and go to next step. If oil drains from opening, go to next step.
  5. With OCV removed, connect fused jumper wires between positive battery terminal and OCV connector terminal No. 1, and negative battery terminal and OCV connector terminal No. 2. See Figure. OCV plunger should move away from connector. Remove fused jumper wires. OCV plunger should move back in direction of connector. If OCV plunger does not move as specified, replace OCV and go to next step. If OCV plunger moves as specified, go to next step.
  6. Check for blockage in OCV. Check oil check valve and oil pipe located under OCV. Repair as necessary. If components are okay, go to next step.
  7. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Duplicate driving conditions under which DTC P1349 was set. Retrieve DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If DTC P1349 is displayed, replace ECM and retest. If DTC P1349 is not displayed, VVT system 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.
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