Diagnosis & Repair
WARNING: This page is about a different car, the 2003 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
- Start engine. If engine speed is normal when disconnecting OCV connector, then idle is rough or engine stalls when applying battery positive voltage between terminals of the OCV, go to next step. If engine speed is not to specification, go to step 3.
- Disconnect the C2 or C3 OCV connector. Apply battery positive voltage between the terminals of the OCV. See Fig 1. Check the engine speed. If idle is rough or engine is stalled, go to next step. If idle is not rough, replace camshaft timing oil control valve assembly.
- Using oscilloscope during idle, check the waveform between terminals E2 (OCV+ and OCV-) and E4 (OCR+ and OCR-) of ECM connectors. The waveform frequency is lengthened as the engine speed becomes higher. See Fig 2. If okay, go to next step. If not okay, check and replace ECM.
- Disconnect C2 or C3 OCV connector. See Fig 3. Disconnect E2 and E4 ECM connectors. See Fig 4. Check the continuity between the wire harness side connectors. If okay, check for intermittent problems. If not okay, repair or replace harness and connector as necessary.