Toyota Avalon (XX50) 2019-2022 Service & Repair Manual: Starter Signal Circuit

DESCRIPTION

While the engine is being cranked, current flows from terminal STAR of the certification ECU (smart key ECU assembly) to the park/neutral position switch assembly and to terminal STA of the ECM (STA signal).

WIRING DIAGRAM

Refer to DTC P061512.

Click here

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

PROCEDURE

1.

CHECK WHETHER ENGINE CAN BE CRANKED

(a) Check if the engine can be cranked.

Result

Proceed to

Engine cannot be cranked

A

Engine can be cranked

B

B

GO TO STEP 12

A

2.

READ VALUE USING TECHSTREAM (STARTER SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Starter SW.

Powertrain > Engine > Data List

Tester Display

Starter SW

(e) Check the value displayed on the Techstream when the engine switch is turned on (IG) and the engine is cranked.

OK:

Condition

Techstream Display (Starter SW)

Engine switch on (IG)

OFF

Cranking position

ON

NG

GO TO STEP 9

OK

3.

INSPECT ST RELAY

(a) Inspect the ST relay.

Click here

NG

REPLACE ST RELAY

OK

4.

INSPECT STARTER ASSEMBLY

(a) Inspect the starter assembly.

Click here

NG

REPLACE STARTER ASSEMBLY

OK

5.

CHECK HARNESS AND CONNECTOR (ST RELAY - STARTER ASSEMBLY)

(a) Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Disconnect the starter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 (ST relay) - C58-1 (ST)

Always

Below 1 Ω

3 (ST relay) or C58-1 (ST) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.

CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND)

(a) Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

1 (ST relay) - Body ground

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.

CHECK HARNESS AND CONNECTOR (BATTERY - STARTER ASSEMBLY)

(a) Disconnect the cable from the negative (-) battery terminal.

(b) Disconnect the cable from the positive (+) battery terminal.

(c) Disconnect the starter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

Positive (+) battery terminal - C70-1 (B)

Always

Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.

CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH ASSEMBLY - SMART KEY ECU ASSEMBLY - ST RELAY)

(a) Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(b) Disconnect the certification ECU (smart key ECU assembly) connector.

(c) Disconnect the park/neutral position switch assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C53-9 (L) - 2 (ST relay)

Always

Below 1 Ω

A10-20 (STA) - 2 (ST relay)

Always

Below 1 Ω

OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - ST RELAY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.

INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

(a) Inspect the park/neutral position switch assembly.

Click here

NG

REPLACE PARK/NEUTRAL POSITION SWITCH ASSEMBLY

OK

10.

CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM - ST RELAY - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))

(a) Disconnect the park/neutral position switch assembly connector.

(b) Disconnect the ECM connector.

(c) Remove the ST relay from the No. 1 engine room relay block and No. 1 junction block assembly.

(d) Disconnect the certification ECU (smart key ECU assembly) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C53-9 (L) - A18-43 (STA)

Always

Below 1 Ω

C53-9 (L), A18-43 (STA), 2 (ST relay) or A10-20 (STA) - Body ground and other terminals

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

11.

CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - PARK/NEUTRAL POSITION SWITCH ASSEMBLY - ECM)

(a) Disconnect the park/neutral position switch assembly connector.

(b) Disconnect the certification ECU (smart key ECU assembly) connector.

(c) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

A10-9 (STAR) - C53-4 (B)

Always

Below 1 Ω

A10-9 (STAR) - C56-106 (NSW)

Always

Below 1 Ω

A10-9 (STAR), C53-4 (B) or C56-106 (NSW) - Body ground and other terminals

Always

10 kΩ or higher

OK

GO TO SMART KEY SYSTEM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

12.

READ VALUE USING TECHSTREAM (STARTER SW)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Starter SW.

Powertrain > Engine > Data List

Tester Display

Starter SW

(e) Check the value displayed on the Techstream when the engine switch is turned on (IG) and the engine is cranked.

OK:

Condition

Techstream Display (Starter SW)

Engine switch on (IG)

OFF

Cranking position

ON

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR (ST RELAY - ECM)

    Rough Idling

    System Diagram

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