P1656

P1656 - OCV Circuit Malfunction

CIRCUIT DESCRIPTION

DTC Detecting Condition:

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

Wiring Diagram:

INSPECTION PROCEDURE

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

Step 1:

Steps 2 - 4:

TOYOTA hand-held tester

Steps 1 - 3:

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

CHECK FOR INTERMITTENT PROBLEMS

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

a. Clear the DTC.
b. Set the check mode.
c. Perform a simulation test.
d. Check the connector and terminal.
e. Handle the connector.