Stop Light Control Relay: Inspection

WARNING: This page is about a different car, the 2009 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT STOP LIGHT CONTROL RELAY ASSEMBLY

Disconnect the S31 stop light control relay assembly connector.

Measure the voltage according to the value(s) in the table below.

Standard Voltage

Tester Connection	Condition	Specified Condition
S31-2 (STP) - Body ground	Brake pedal released	Below 1 V
S31-2 (STP) - Body ground	Brake pedal depressed	11 to 14 V
S31-6 (+B) - Body ground	Always	11 to 14 V

If the result is not as specified, there is a malfunction on the wire harness side.

Fig 1: Identifying Stop Light Control Relay Assembly Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition
S31-4 (GND) - Body ground	Always	Below 1Ω

If the result is not as specified, there is a malfunction on the wire harness side.