Toyota Yaris: Stop And Start System / STA Signal Circuit

Toyota Yaris XP210 (2020-2026) Reapir and Service Manual / Engine & Hybrid System / Stop And Start / Stop And Start System / STA Signal Circuit

DESCRIPTION

While the engine is being cranked, a starter operation request signal is sent to terminal STA of the ECM.

HINT:

If there is an open in the STA circuit of the ECM, stop and start control will be prohibited after the third time the engine is started by stop and start control.

Stop and start control will be prohibited until the ignition switch is turned off.
The MIL will not illuminate.
If there is an open in the STA circuit of the ECM, the engine can still be started using the ignition switch, as the ECM also receives the starter operation request signal from the engine stop and start ECU via CAN communication. (Stop and start control is prohibited as the reliability of the signal sent via CAN communication cannot be assured while the voltage drops during operation of the starter assembly.)

WIRING DIAGRAM

PROCEDURE

1.	READ VALUE USING GTS (STARTER SW)

Powertrain > Engine > Data List

Tester Display
Starter SW

(a) Read the values displayed on the GTS when the ignition switch is ON and on (START).

OK:

GTS Display	Switch Condition	Normal Condition
Starter SW	Ignition switch ON	OFF
Starter SW	Ignition switch START	ON

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	CHECK HARNESS AND CONNECTOR (ECM - ST NO. 1 RELAY)

(a) Disconnect the A67 engine stop and start ECU connector.

(b) Disconnect the A106 ECM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A106-30 (STA) - ST NO. 1 relay terminal 2	Always	Below 1 Ω

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPAIR OR REPLACE HARNESS OR CONNECTOR

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