| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
The VVT system controls the intake valve timing in response to driving conditions. ECM uses impute from Crankshaft Position (CKP) sensor and Camshaft Position (CMP) to control the Oil Control Valve (OCV). OCV varies oil pressure between 2 circuits changing intake camshaft position as much as 60 degrees of crankshaft angle.
DTC P1656 is set when ECM detects an open or short in OCV circuit. Possible causes are
- Open or short in oil OCV circuit.
- Oil control valve.
- ECM.