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Home >> Toyota >> 2002 >> Corolla CE, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System Self-Diagnostics >> Diagnostic Tests >> DTC P1349: Variable Valve Timing System Malfunction >> Diagnosis & Repair (Using OBD-II Scan Tool)
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Diagnosis & Repair (Using OBD-II Scan Tool)

  1. Check valve timing. See appropriate article in ENGINES. If problem exists, repair as necessary. If problem does not exist, go to next step.
  2. Start engine and allow it to idle. Disconnect Variable Valve Timing (VVT) Oil Control Valve (OCV) and note idle speed. VVT OCV is located on front cylinder head, next to intake manifold. Engine idle speed should not change. Using jumper wires, apply battery voltage and ground to VVT OCV terminals (component side). Engine should idle rough or stall. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, go to step  4.
  3. Turn ignition off. Connect VVT OCV harness connector. Access ECM below stereo, behind instrument panel, just in front of center console. See Figure. Using oscilloscope, backprobe ECM harness connector. On models with 3-speed A/T and M/T, connect oscilloscope between terminals No. 1 (Red wire) and No. 2 (Black wire) at ECM harness connector E4. See Figure. On models with 4-speed A/T transmission, connect oscilloscope between terminals No. 23 (Red wire) and No. 24 (Black wire) at ECM harness connector E7. See Figure. On all applications, 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, no problem is indicated 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 waveform pattern is not as shown, replace ECM.
  4. Check VVT controller assembly for proper operation. See appropriate article in ENGINES. If problem exists, replace VVT controller assembly and go to next step. If problem does not exist, go to next step.
  5. Disconnect VVT OCV harness connector. Measure resistance between VVT OCV terminals (component side). Resistance should be 6.9-7.9 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace VVT OCV.
  6. Remove VVT OCV. Connect a fused jumper wire between positive battery terminal and terminal No. 1 at VVT OCV. See Figure. Connect another jumper wire between negative battery terminal and terminal No. 2 at VVT OCV and note VVT OCV plunger operation. With battery voltage applied, plunger on end of VVT OCV should extend. Disconnect a jumper wire. Without battery voltage applied, plunger should retract. If VVT OCV operates as specified, go to next step. If VVT OCV does not operate as specified, replace VVT OCV and go to next step.
  7. Check blockage in VVT OCV. Check oil check valve and oil pipe located under VVT OCV. If problem exists, repair as necessary. If problem does not exist, go to next step.
  8. Install remove components all and connect all disconnected harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Turn ignition off. Turn ignition on and check for DTCs. If DTC P1349 is not present, no problem is indicated 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 DTC P1349 is present, replace ECM.
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