Theft Deterrent / Keyless Entry

Unlock Warning Switch Circuit

~2min read
DESCRIPTION

The key unlock warning switch assembly turns on when the ignition key is inserted into the ignition key cylinder and turns off when the ignition key is removed.

The main body ECU (driver side junction block assembly) operates the key confinement prevention function while the key unlock warning switch assembly is on.

WIRING DIAGRAM
PROCEDURE
  1. READ VALUE USING TECHSTREAM (UNLOCK WARNING SWITCH ASSEMBLY)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Select the item below in the Data List and then read the display on the Techstream.

Main Body

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Key Unlock Warning SW

Unlock warning switch signal/ON or OFF

ON: Key inserted into ignition key cylinder

OFF: Key removed from ignition key cylinder

-

OK:

When the key is in the ignition key cylinder, ON appears on the Techstream.


OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG
  1. INSPECT UNLOCK WARNING SWITCH ASSEMBLY

(a) Remove the unlock warning switch assembly (See page ).

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D24-1 (UN+) - D24-2 (UN-)

Free

(Key removed)

10 kΩ or higher

D24-1 (UN+) - D24-2 (UN-)

Pushed

(Key set)

Below 1 Ω

Text in Illustration

*1

Component without harness connected

(Unlock Warning Switch Assembly)


NG

REPLACE UNLOCK WARNING SWITCH ASSEMBLY

OK
  1. CHECK HARNESS AND CONNECTOR (UNLOCK WARNING SWITCH ASSEMBLY - BODY GROUND)

(a) Disconnect the D24 unlock warning switch assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D24-2 (UN-) - Body ground

Always

Below 1 Ω

Text in Illustration

*1

Front view of wire harness connector

(to Unlock Warning Switch Assembly)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
  1. CHECK HARNESS AND CONNECTOR (UNLOCK WARNING SWITCH ASSEMBLY - MAIN BODY ECU)

(a) Disconnect the D51 main body ECU (driver side junction block assembly) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D24-1 (UN+) - D51-5 (KSW)

Always

Below 1 Ω

Text in Illustration

*1

Front view of wire harness connector

(to Main Body ECU (Driver Side Junction Block Assembly))

*2

Front view of wire harness connector

(to Unlock Warning Switch Assembly)


OK

REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

Test yourself

A quick Toyota Venza quiz: every answer comes with an explanation and a link to the manual page.