Toyota Sienna Service Manual: Cranking Holding Function Circuit
DESCRIPTION
The system detects the ignition switch's starting signal (STSW) and then
supplies current to the starter
until the ECM judges that the engine has started successfully. The purpose is to
reduce the holding time
of the ignition key.

WIRING DIAGRAM
Refer to DTC P0617.
INSPECTION PROCEDURE
1 CHECK CRANKING
- When starting the engine, check whether the starter
motor starts.
OK:
Engine is cranking.
2 READ VALUE OF INTELLIGENT TESTER (STA SIGNAL)
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to the ON position.
- Turn the tester on.
- Select the following menu items: DIAGNOSIS /
ENHANCED OBDII / DATA LIST / ALL / STARTER SIG.
- Check the result when the ignition switch is turned ON
and when the engine is started.
OK

3 CHECK ECM (STAR AND STSW VOLTAGE)

- Measure the voltage between the terminals of the ECM
connector and body ground while cranking the engine.
Standard voltage

Result

4 INSPECT PARK/NEUTRAL POSITION SWITCH ASSEMBLY

- Inspect the Park/Neutral Position (PNP) switch.
- Disconnect the P1 PNP switch connector.
- Measure the resistance according to the value(s) in
the table below.
Standard resistance

- Reconnect the PNP switch connector.
5 CHECK HARNESS AND CONNECTOR (IGNITION SWITCH - PARK/NEUTRAL POSITION
SWITCH)

- Disconnect the I15 ignition switch connector.
- Disconnect the P1 park/neutral position switch
connector.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance (check for open)

Standard resistance (check for short)

- Reconnect the ignition switch connector.
- Reconnect the park/neutral position switch connector.
REPAIR OR REPLACE HARNESS OR CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ECM)
6 INSPECT ST RELAY

- Remove the ST relay from the No. 3 relay block.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance

- Reinstall the ST relay to the No. 3 relay block.
7 CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ST RELAY)

- Disconnect the P1 park/neutral position switch
connector.
- Remove the ST relay from the No. 3 relay block.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance (check for open)

Standard resistance (check for short)

- Reconnect the park/neutral position switch connector.
- Reinstall the ST relay to the No. 3 relay block.
8 CHECK HARNESS AND CONNECTOR (ST RELAY - BODY GROUND)

- Remove the ST relay from the No. 3 relay block.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance

- Reinstall the ST relay to the No. 3 relay block.
9 CHECK ST RELAY (POWER SOURCE)

- Remove the ST relay from the No. 3 relay block.
- Measure the voltage according to the value(s) in the
table below.
Standard voltage

- Reinstall the ST relay to the No. 3 relay block.
10 INSPECT FUSIBLE LINK

- Remove the fusible link block from the engine room
junction block.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance

- Reinstall the fusible link block to the engine room
junction block
REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - STARTER RELAY)
11 INSPECT STARTER ASSEMBLY
- Inspect the starter assembly
12 CHECK HARNESS AND CONNECTOR (ST RELAY - STARTER ASSEMBLY)

- Remove the ST relay from the No. 3 relay block.
- Disconnect the S4 starter connector.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance (check for open)

Standard resistance (check for short)

- Reconnect the starter connector.
- Reinstall the ST relay to the No. 3 relay block.
REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - STARTER ASSEMBLY)
13 INSPECT FUSE (ST FUSE)

- Remove the ST fuse from the fuse box.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance

- Reinstall the ST fuse.
14 INSPECT IGNITION SWITCH ASSEMBLY

- Disconnect the I15 ignition switch connector.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance

- Reconnect the ignition switch connector
15 CHECK HARNESS AND CONNECTOR (ECM - IGNITION SWITCH ASSEMBLY)

- Disconnect the E11 ECM connector.
- Disconnect the I15 ignition switch connector.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance (check for open)

Standard resistance (check for short)

- Reconnect the ECM connector.
- Reconnect the ignition switch connector.
REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH - BATTERY)
DESCRIPTION
The FUEL PUMP relay switches the fuel pump speed according to the engine
conditions. The fuel pump
operates when the ECM receives the starter-operating signal (STA) and
crankshaft-ro ...
DESCRIPTION
This circuit opens and closes the Intake Air Control Valve (IACV) in response
to changes in the engine
load in order to increase the intake efficiency (ACIS: Acoustic Control
Inducti ...
Other materials:
Customer problem analysis
HINT:
In troubleshooting, confirm that the problem symptoms
have been accurately identified. Preconceptions should be
discarded in order to make an accurate judgment. To
clearly understand what the problem symptoms are, it is
extremely important to ask the customer about the
problem an ...
For vehicles equipped with vehicle stability control (vsc) system
(a) Notices when using drum tester
Notices when using drum tester.
(1) When using a drum tester, be sure to start the
engine with the ignition switch OFF, and connect
SST to the terminals TS and CG of the DLC3
before the measurement in order to cancel the
VSC operation.
SST 09843-18040
...
System description
1. BRIEF DESCRIPTION
The CAN (Controller Area Network) is a serial data
communication system for real time application. It is
a vehicle multiplex communication system which
has a high communication speed (500 kbps) and
the ability to detect malfunctions.
By pairing the CANH and CANL bu ...