P1656

DTC P1656 OCV Circuit Malfunction (Bank 1)

CIRCUIT DESCRIPTION

DTC Detection Condition:

The VVT system controls the intake valve timing properly according to the driving condition. The ECM controls OCV (Oil Control Valve) to make the intake valve timing properly, and the oil pressure controlled with the OCV is supplied to the VVT controller. And then the VVT controller changes relative position between the camshaft and the crankshaft.

Wiring Diagram:

INSPECTION PROCEDURE

HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool, as freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, this is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

Step 1 - 2:

Step 3 - 4:

TOYOTA hand-held tester

Step 1:

Step 2 - 3:

OBD II scan tool (excluding TOYOTA hand-held tester)

CHECK FOR INTERMITTENT PROBLEMS

TOYOTA hand-held tester only:
By putting the vehicle's ECM in the check mode, 1 trip detection logic is possible instead of 2 trip detection logic and the sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.

1. Clear the DTCs.
2. Set the check mode.
3. Perform a simulation test.
4. Check the connector and terminal.
5. Handle the connector.