Toyota Yaris: Stop And Start System / Starter Inrush Current Reduction Relay Circuit

Toyota Yaris XP210 (2020-2024) Reapir and Service Manual / Engine & Hybrid System / Stop And Start / Stop And Start System / Starter Inrush Current Reduction Relay Circuit

DESCRIPTION

The starter inrush current reduction relay prevents the auxiliary battery voltage from becoming dropping excessively while the starter assembly is operating. If the auxiliary battery voltage drops below the threshold, stop and start control will be prohibited. In order to prevent this, the engine stop and start ECU operates the starter inrush current reduction relay for approximately 0.1 seconds after the ST NO. 1 relay is activated. By allowing current to flow to the starter inrush current reduction relay, the current that flows to the starter motor is reduced, preventing the auxiliary battery voltage from dropping excessively.

CAUTION / NOTICE / HINT

HINT:

Starter inrush current reduction relay stuck on:
When the engine is started by stop and start control, a large amount of current will flow to the starter assembly, the auxiliary battery voltage will drop excessively and stop and start control will be canceled.
Starter inrush current reduction relay stuck off:
Operating current will always flow through the starter inrush current reduction relay and the cranking speed will be low.
For wire harness and connector inspection procedures and precautions, refer to " "

PROCEDURE

1.	CHECK WAVEFORM (STARTER INRUSH CURRENT REDUCTION RELAY)

(a) Connect the positive (+) lead of an oscilloscope to the positive (+) auxiliary battery terminal and the negative (-) lead to the negative (-) auxiliary battery terminal.

(b) While cranking the engine, count the number of times the waveform drops.

Standard:

Waveform drops 2 times

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPLACE STARTER INRUSH CURRENT REDUCTION RELAY

After Engine Stops due to Stop and Start System, Engine does not Restart

DESCRIPTION This is the troubleshooting procedure for situations where the engine does not restart after having been stopped by the stop and start system...

Failure to Restart from IG-ON Engine Stall

DESCRIPTION This is the troubleshooting procedure for situations where the engine does not restart when attempting to restart it after either a failed engine start occurred under stop and start system control, or a mis-operation during vehicle takeoff resulted in an engine stall...

Other information:

Toyota Yaris XP210 (2020-2024) Owner's Manual: Tire Pressure Monitoring System (If equipped)

The Tire Pressure Monitoring System (TPMS) monitors the air pressure of all four tires. If the air pressure of one or more tires is too low, the system warns the driver by indicating the tire pressure monitoring system warning light in the combination meter and operating a beep sound...

Toyota Yaris XP210 (2020-2024) Reapir and Service Manual: Operation not Accepted Even If Air Conditioning Switch is Operated

DESCRIPTION If the air conditioning system cannot be operated using the air conditioning control assembly, the following factors may be the cause. Symptom Factor Air conditioning system cannot be operated using air conditioning control assembly (With the exception of the switch indicators, no inputs are reflected when other switches operated) LIN communication malfunction between air conditioning amplifier assembly and air conditioning control assembly Short to +B or ground in air conditioning amplifier assembly circuit Air conditioning amplifier assembly malfunction Air conditioning control assembly malfunction Harness or connector WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: Inspect the fuses for circuits related to this system before performing the following procedure...