Entry And Start System - Engine Does Not Start

Lexus IS250 IS220d GSE20 ALE20 2AD-FHV STARTING

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK IF ENGINE START (INITIALIZE STEERING LOCK)

CHECK FOR DTC

CHECK SWITCH CONDITION

CHECK CRANKING FUNCTION

READ VALUE OF INTELLIGENT TESTER (STA SIGNAL)

READ VALUE OF INTELLIGENT TESTER (STEERING LOCK)

CHECK STEERING LOCK

INSPECT ECM (STAR AND STSW VOLTAGE)

INSPECT RELAY (ST CUT)

INSPECT CLUTCH START SWITCH

INSPECT RELAY (STARTER)

CHECK HARNESS AND CONNECTOR (CLUTCH START SWITCH - ST RELAY)

INSPECT ENGINE ROOM RELAY BLOCK (STARTER RELAY VOLTAGE)

INSPECT STARTER ASSEMBLY

CHECK HARNESS AND CONNECTOR (POWER SOURCE CONTROL ECU - ECM)

CHECK AND REPLACE POWER SOURCE CONTROL ECU

READ VALUE OF INTELLIGENT TESTER (L CODE)

READ VALUE OF INTELLIGENT TESTER (ENGINE START REQUEST)

READ VALUE OF INTELLIGENT TESTER (S CODE)

INSPECT ID CODE BOX

CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - STEERING LOCK ECU)

INSPECT POWER SOURCE CONTROL ECU

INSPECT STEERING LOCK ECU

ENTRY AND START SYSTEM - Engine does not Start

DESCRIPTION

ENGINE START SYSTEM OPERATION

If the engine switch is pressed with the clutch pedal depressed, the power source control ECU determines that it is an engine start request.

The certification ECU and other ECUs perform key verification via the LIN communication line.

The power source control ECU activates the ACC relay.

The power source control ECU activates the IG1 and IG2 relays.

The certification ECU outputs a steering UNLOCK signal. The signal is sent to the power source control ECU via the steering lock ECU.

The power source control ECU sends an engine start request signal to the ECM.

The ECM sends an ACC cut request signal to the power source control ECU.

The ECM and power source control ECU activate the ST relay.

The power source control ECU deactivates the ACC relay until the ECU detects an engine start.

When engine revolution speed reaches 200 rpm, the power source control ECU determines that the engine has been started.


The ECU reactivates the ACC relay and turns off the engine switch indicator light.

Symbols of power source control ECUSignals
SSW1/SSW2Engine switch ON signal
ACCDACC relay operation signal
IG2DIG2 relay operation signal
STR2ST relay operation signal
STR1Clutch start switch
TACHEngine start detection signal
STSWStarter activation request signal
CTSWACC cut request signal

Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

WIRING DIAGRAM

See CRANKING HOLDING FUNCTION CIRCUIT .


INSPECTION PROCEDURE

1.CHECK IF ENGINE START (INITIALIZE STEERING LOCK)

Open and close the driver's door with the engine switch off. Check if the engine can be started.

  • OK:
  • Engine can be started.
  • HINT:
  • After the battery is discharged and then recharged, the engine may not start unless the steering lock is initialized using the above procedure.
OK
Go to step 17
NG
5.READ VALUE OF INTELLIGENT TESTER (STA SIGNAL)

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Check the result when the engine switch is turned on (IG) and the engine is started.

Standard:
Engine Switch PositionON (IG)ENGINE START
St Relay MonOFFON
  • OK:
  • ON (ENGINE START) and OFF (ENGINE SWITCH ON (IG)) appear on the screen.
OK
Go to step 11
NG
6.READ VALUE OF INTELLIGENT TESTER (STEERING LOCK)

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Power Source Control:
ItemMeasurement Item/Display (Range)Normal ConditionDiagnostic Note
Str Unlock SWSteering lock condition/ ON or OFFON: Steering is unlocked
OFF: Steering is locked		-
  • OK:
  • ON (steering is unlocked) and OFF (steering is locked) appear on the screen.
NG
Go to step 21
OK
7.CHECK STEERING LOCK

Check if the steering lock is released when turning the engine switch on (ACC).

  • OK:
  • The steering lock is released.
NG
Go to step 15
A
9.INSPECT RELAY (ST CUT)
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Remove the ST CUT relay from the engine room J/B and R/B No. 2.

Measure the resistance of the ST CUT relay.

  • Standard resistance:
  • Tester ConnectionSpecified Condition
    3 - 510 kΩ or higher
    3 - 5Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)
NG
REPLACE RELAY
OK
10.INSPECT CLUTCH START SWITCH
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Disconnect the clutch switch connector.

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

  • Standard resistance:
  • Clutch Pedal OperationTester ConnectionSpecified Condition
    Depressed1 - 2Below 1 Ω
    Released1 - 210 kΩ or higher
NG
REPLACE CLUTCH START SWITCH
OK
CHECK AND REPLACE HARNESS AND CONNECTOR (CLUTCH START SWITCH - ECM, ECM - ST CUT RELAY, ST)
11.INSPECT RELAY (STARTER)
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Remove the starter relay from the engine room J/B and R/B No. 1.

Measure the resistance of the starter relay.

  • Standard resistance:
  • Tester ConnectionSpecified Condition
    3 - 510 kΩ or higher
    3 - 5Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)
NG
REPLACE RELAY
OK
12.CHECK HARNESS AND CONNECTOR (CLUTCH START SWITCH - ST RELAY)
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Check the harness and the connector between the starter relay.


Disconnect the A24 switch connector.

Remove the starter relay from the engine room J/B and R/B No. 1.

Measure the resistance of the wire harness side connectors.

  • Standard resistance (Check for open):
  • Tester ConnectionSpecified Condition
    Clutch start switch (A24-2) - Starter relay (1)Below 1 Ω
  • Standard resistance (Check for short):
  • Tester ConnectionSpecified Condition
    Clutch start switch (A24-2) or Starter relay (1) - Body ground10 kΩ or higher

Check the harness and the connector between the starter relay and the body ground.


Remove the starter relay from the engine room J/B and R/B No. 1.

Measure the resistance of the starter relay and the body ground.

  • Standard resistance (Check for open):
  • Tester ConnectionSpecified Condition
    Starter relay (2) - Body groundBelow 1 Ω
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
13.INSPECT ENGINE ROOM RELAY BLOCK (STARTER RELAY VOLTAGE)
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Remove the starter relay from the engine room J/B and R/B No. 1.

Measure the voltage of the engine room J/B and R/B No. 1 and the body ground.

  • Standard voltage:
  • Tester ConnectionSpecified Condition
    Starter relay (5) - Body ground9 to 14 V
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
14.INSPECT STARTER ASSEMBLY
  • HINT:
NG
REPAIR OR REPLACE STARTER ASSEMBLY
OK
REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER RELAY - STARTER, STARTER - BATTERY)
15.CHECK HARNESS AND CONNECTOR (POWER SOURCE CONTROL ECU - ECM)
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Check the harness and the connectors between the power source control ECU and ECM.


Disconnect the power source control ECU connector.

Disconnect the A49 ECM connector.

Measure the resistance of the wire harness side connectors.

  • Standard resistance (Check for open):
  • Tester ConnectionSpecified Condition
    J55-39 (STSW) - A49-9 (STSW)Below 1 Ω
  • Standard resistance (Check for short):
  • Tester ConnectionSpecified Condition
    J55-39 (STSW) or A49-9 (STSW) - Body ground10 kΩ or higher
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
16.CHECK AND REPLACE POWER SOURCE CONTROL ECU

Replace the power source control ECU.

Check the engine cranking function.


When there is fuel in the tank and the key is inside the vehicle, check that depressing the clutch pedal and the brake pedal and pressing the engine switch crank the engine.

  • OK:
  • Engine cranks.
  • HINT:
  • After the power source control ECU is replaced the engine may not start unless the each system are initialized using the above procedure.
NG
REPLACE ECM
OK
END
17.READ VALUE OF INTELLIGENT TESTER (L CODE)

Reconnect the connectors.

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Entry & Start:
ItemMeasurement Item/Display (Range)Normal ConditionDiagnostic Note
L Code ChkL code check/ ON or NGOK: Normal
NG: Malfunction		Electrical key in the cabin
  • OK:
  • OK is displayed on the screen.
  • HINT:
  • If the result of the inspection for a tester display is not as specified, there may be malfunction of the steering lock ECU or the ID code box.
NG
GO TO ENGINE IMMOBILISER SYSTEM
OK
18.READ VALUE OF INTELLIGENT TESTER (ENGINE START REQUEST)

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Entry & Start:
ItemMeasurement Item/Display (Range)Normal ConditionDiagnostic Note
Start RqstStart request signal response/ OK or NGOK: Received
NG: Non-received		-
  • OK:
  • OK (received) and NG (non-received) appear on the screen.
NG
REPLACE CERTIFICATION ECU
OK
19.READ VALUE OF INTELLIGENT TESTER (S CODE)

Connect the intelligent tester to the DLC3.

Turn the engine switch on (IG).

Entry & Start:
ItemMeasurement Item/Display (Range)Normal ConditionDiagnostic Note
S Code ChkS code check/ OK or NGOK: Normal
NG: Malfunction		-
  • OK:
  • OK is displayed on the screen.
  • HINT:
  • If the result of the inspection for a tester display is not as specified, there may be malfunction of the certification ECU or the ID code box.
NG
GO TO ENGINE IMMOBILISER SYSTEM
OK
20.INSPECT ID CODE BOX
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Check the input signal waveform.


Connect the oscilloscope to the terminals J69-6 (EFIO) and J69-5 (EFII).

Turn the engine switch on (IG).

Check the signal waveform according to the condition(s) in the table below.

ItemCondition
Tool setting10 V/DIV., 100 ms./DIV.
Vehicle conditionEngine switch on (IG)
NG
REPLACE ID CODE BOX
OK
END
21.CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - STEERING LOCK ECU)
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Disconnect the ECU connector.

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

  • Standard resistance:
  • Tester Connection (Symbols)Specified Condition
    J55-26 (SLP) - J29-4 (SLP1)Below 1 Ω
    J55-26 (SLP) or J29-4 (SLP1) - Body ground10 kΩ or higher
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
22.INSPECT POWER SOURCE CONTROL ECU
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Reconnect the J55 ECU connector.

Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Connect the oscilloscope to the power source control ECU terminals specified in the table below and check the waveform.

ItemContents
Terminal (Symbols)J55-26 (SLP) - Body ground
Equipment Setting2 V/DIV., 100 ms./DIV.
ConditionEngine switch on (IG)
  • OK:
  • The waveform appears as shown in the illustration.
NG
REPLACE POWER SOURCE CONTROL ECU
OK
23.INSPECT STEERING LOCK ECU
Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Reconnect the J29 ECU connector.

Entry And Start System - Engine Does Not Start. 2AD-FHV STARTING. Lexus IS250 IS220d GSE20 ALE20

Connect the oscilloscope to the power source control ECU terminals specified in the table below and check the waveform.

ItemContents
Terminal (Symbols)J55-26 (SLP) - Body ground
Equipment Setting2 V/DIV., 100 ms./DIV.
ConditionSteering is LOCK / UNLOCK
  • OK:
  • The waveform appears as shown in the illustration.
NG
REPLACE STEERING LOCK ECU
OK
REPLACE POWER SOURCE CONTROL ECU