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Home >> Lexus >> 2000 >> SC 400 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1349 Or P1354: Variable Valve Timing (VVT) >> Diagnosis & Repair (Using Lexus Scan Tool)

Diagnosis & Repair (Using Lexus Scan Tool)

  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 the 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. Start engine. For left OCV, using oscilloscope, check waveform pattern between terminals No. 19 (Red/Black wire) and No. 20 (Black/White wire) at ECM E15 connector. See Figure. For right OCV, using oscilloscope, check waveform pattern between terminals No. 19 (White/Red wire) and No. 28 (Green/Yellow wire) at ECM E18 connector. On all applications, 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 suspect OCV from cylinder head. Place a shop towel under OCV cylinder head opening. Rotate appropriate VVT pulley from left to right about 25 degrees, 2-3 times. Oil should drain from OCV cylinder head opening. If oil does not drain from opening, replace suspect VVT pulley/gear assembly and go to next step. If oil drains from opening, go to next step.
  5. With suspect 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 suspect OCV and go to next step. If OCV plunger moves as specified, go to next step.
  6. Check for blockage in suspect OCV. Check oil check valve and oil passage located under suspect OCV. Repair as necessary. If components are okay, go to next step.
  7. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. Duplicate driving conditions under which caused DTC P1349 or P1354 to set. Retrieve DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - INTRODUCTION article. If DTC P1349 or P1354 is set, replace ECM and retest. If DTC P1349 or P1354 is not set, VVT system is functioning properly at this time. DTC may have been set because of a foreign object that was temporarily caught in the engine oil system but after a short time system returned to normal.
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