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Home >> Toyota >> 2000 >> RAV4 Base, AWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 1 (Engine Control System Self-Diagnostics) >> Diagnostic Tests >> DTC P1656 Or P1663: Oil Control Valve (OCV) Malfunction >> Diagnosis & Repair (Using OBD-II Scan Tool)
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Diagnosis & Repair (Using OBD-II Scan Tool)

WARNING: This page is about a different car, the 2000 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
  1. Start engine and allow it to idle. Disconnect suspect Oil Control Valve (OCV) and note idle speed. OCV is located in each cylinder head, underneath lower intake manifold. Engine idle speed should not change. Using jumper wires, apply battery voltage to OCV. Engine should idle rough or stall. If OCV operates as specified, go to next step. If OCV does not operate as specified, replace OCV.
  2. Access ECM behind passenger's side kick panel. Using oscilloscope, backprobe ECM harness connector. If checking OCV for bank No. 1 (right cylinder head), connect oscilloscope between terminals No. 18 (Red/White wire) and No. 29 (Red/Blue wire) at ECM harness connector E4. See Figure. If checking OCV for bank No. 2 (left cylinder head), connect oscilloscope between terminals No. 5 (Red wire) and No. 6 (Red/Black wire) at ECM harness connector E4. 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, go to next step. If waveform pattern is not as shown, replace ECM.
  3. Check for an open or short in wiring between suspect 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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