P17F9 – Ratio Monitoring Shift 4-2

P17F9 Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P17F9 Possible Causes

Transmission Mechanical Problems,Faulty Transmission Assembly

P17F9 Description

The Transmission Control Module (TCM) monitors the Shift Ratio. The TCM sets the OBDII code when the Shift Ratio is not to factory specifications.