DTC P0617 Starter Relay Circuit High: Description

The cranking holding control system keeps energizing the ST relay after the ECM detects the starter signal (STSW signal) from the main body ECU until the ECM performs a judgment of "Engine started". Furthermore, the ECM outputs an accessory cut signal (ACCR signal) to the ACC relay during cranking to prevent flickering of the combination meter, clock, audio system, and so on. When the ECM detects the STSW signal, the ECM outputs the starter relay drive signal (STAR signal) to the starter relay through the clutch start switch or park/neutral position switch, and then, the engine is cranked. When the ECM receives a stable engine speed signal (NE signal), more specifically, when the NE signal reaches a predetermined value, the ECM stops outputting the STAR signal. Also, the ECM monitors the ST relay operating conditions based on the STA terminal voltage status.

Fig 1: STSW And ACCR Voltage Signal Graph

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

While the engine is being cranked, the positive battery voltage is applied to terminal STA of the ECM. If the ECM detects the Starter Control (STA) signal while the vehicle is being driven, it determines that there is a malfunction in the STA circuit. The ECM then illuminates the MIL and sets the DTC. This monitor runs when the vehicle is driven at 20 km/h (12.4 mph) for over 20 seconds.