Toyota Tacoma (2015-2018) Service Manual: Engine does not Start

DESCRIPTION

When the key is in the vehicle and the engine switch is pressed, the certification ECU (smart key ECU assembly) receives a signal and changes the power source mode. In addition, when the shift lever is in P or N and the brake pedal is depressed, the engine can be started by pressing the engine switch.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Related Data List and Active Test Items

Problem Symptom	Data List Item	Active Test Item
Engine does not start	Power Source Control Stop Light Switch1 Steering Unlock Switch Power Supply Condition IG Relay Monitor(Inside) IG Relay Monitor(Outside) Latch Circuit Shift P Signal Neutral SW/ Clutch SW Starter Request Signal Smart Key L Code Check Engine Start Request Immobiliser Starting Control Ignition Starter SW Shift Position P or N	-

HINT:

If the brake pedal is repeatedly depressed while the engine is stopped, the brake booster pressure is released and the force required to depress the brake pedal to illuminate the stop lights increases.

PROCEDURE

1.	CHECK ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY

(a) Press a switch of the electrical key transmitter sub-assembly.

OK:

The electrical key transmitter sub-assembly LED illuminates.

NG

GO TO STEP 11

OK

2.	READ VALUE USING TECHSTREAM (KEY LOW BATTERY)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Smart Key / Data List.

(e) Read the Data List according to the display on the Techstream.

Smart Key

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Key Low Battery	Transmitter battery depleted/Yes or No	YES: Transmitter battery depleted NO: Transmitter battery not depleted	The electrical key transmitter sub-assembly sends voltage information to the certification ECU (smart key ECU assembly) when it is transmitting. The certification ECU (smart key ECU assembly) displays "YES" for the "Key Low Battery" item of the Data List when this voltage information indicates 2.2 V or less. This Data List item should be checked when the electrical key transmitter sub-assembly is at room temperature (example: at -20°C (-4°F), "YES" may be displayed even if the transmitter battery is new).

Result

Result	Proceed to
"NO" is displayed on the Techstream screen	A
"YES" is displayed on the Techstream screen	B

B

REPLACE TRANSMITTER BATTERY

A

3.	CHECK WAVE ENVIRONMENT

(a) If the problem occurs in certain locations or times of day, the possibility of wave interference is high.

HINT:

Whether the problem is due to wave interference can be checked by holding the electrical key transmitter sub-assembly near the electrical key and TPMS receiver assembly.

OK:

Engine starts.

Result

Result	Proceed to
NG	A
OK	B

B

AFFECTED BY WAVE INTERFERENCE

A

4.	CHECK ENGINE SWITCH CONDITION

(a) Get into the vehicle while carrying an electrical key transmitter sub-assembly.

(b) Move the shift lever to P.

(c) With the brake pedal released, check that pressing the engine switch causes the power source mode to change.

Result

Result	Proceed to
Power source mode changes: Off → on (ACC) → on (IG) → off	A
Power source mode does not change to on (ACC) or on (IG)	B
Power source mode changes to on (IG) but not to on (ACC)	C
Power source mode changes to on (ACC) but not to on (IG)	D

B

GO TO POWER SOURCE MODE DOES NOT CHANGE TO ON (IG AND ACC)

C

GO TO POWER SOURCE MODE DOES NOT CHANGE TO ON (ACC)

D

GO TO POWER SOURCE MODE DOES NOT CHANGE TO ON (IG)

A

5.	READ VALUE USING TECHSTREAM (NEUTRAL SW / CLUTCH SW, SHIFT POSITION P OR N)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Power Source Control or Starting Control / Data List.

(e) Read the Data List according to the display on the Techstream.

Power Source Control

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Neutral SW/ Clutch SW	Shift position (P and N)/ON or OFF	ON: Shift lever in P or N OFF: Shift lever in any position other than P or N	Use this item to determine whether the park/neutral position switch is malfunctioning. When the engine cannot be started due to a park/neutral position switch malfunction, OFF is displayed.

Starting Control

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Shift Position P or N	Park/neutral position switch status/ON or OFF	ON: Shift lever in P OFF: Shift lever not in P	When malfunctioning, the engine will not crank.

OK:

The Techstream display changes correctly in response to the shift position.

NG

GO TO STEP 23

OK

6.	CHECK FOR DTC

(a) Using the Techstream, check for certification ECU (smart key ECU assembly) DTCs (See page ).

Result

Result	Proceed to
DTCs are not output	A
Smart key system (for Start Function) DTCs are output	B

B

GO TO DIAGNOSTIC TROUBLE CODE CHART

A

7.	READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH1)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Power Source Control / Data List.

(e) Read the Data List according to the display on the Techstream.

Power Source Control

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Stop Light Switch1	State of brake pedal/ON or OFF	ON: Brake pedal depressed OFF: Brake pedal released	Use this item to determine whether the stop light switch is malfunctioning. The engine cannot be started when this item is OFF. If the stop light switch is malfunctioning, the engine can be started by pressing and holding the engine switch for a certain period of time.

OK:

The Techstream display changes correctly in response to the brake operation.

NG

GO TO STEP 21

OK

8.	READ VALUE USING TECHSTREAM (STARTER REQUEST SIGNAL)

(a) Connect the Techstream to the DLC3.

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

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Power Source Control / Data List.

(e) Read the Data List according to the display on the Techstream.

Power Source Control

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Starter Request Signal	Engine start request signal status/ON or OFF	ON: With the shift lever in P and the brake pedal depressed, the engine switch is pressed and held OFF: After approx. 1 second has elapsed, the engine switch is released	When the engine cannot be started due to a start request signal malfunction, OFF is displayed. When the engine switch is pressed, the duration of time that ON is displayed will be extremely short. As such, the engine switch needs to be pressed and held for a certain period of time.

NOTICE:

Check that the key indicator is displayed on the multi-information display in the combination meter assembly, and then press the engine switch.

OK:

The Techstream display changes correctly in response to the engine switch operation.

NG

GO TO STEP 12

OK

9.	CHECK STEERING LOCK

(a) Check that the steering unlocks when the engine switch is turned on (ACC).

OK:

The steering unlocks.

NG

GO TO STEERING LOCK SYSTEM (UNABLE TO UNLOCK STEERING)

OK

10.	CHECK SECURITY INDICATOR LIGHT (IMMOBILISER SYSTEM UNSET)

(a) Get into the vehicle while carrying an electrical key transmitter sub-assembly.

(b) Move the shift lever to P.

(c) Press the engine switch with the brake pedal released and check that the security indicator light changes from blinking to off at the same time that the power source mode changes to on (ACC).

HINT:

The immobiliser function can be determined to be operating correctly if the security indicator light changes from blinking to off at the same time that the power source mode changes to on (ACC).

OK:

The security indicator light changes from blinking to off at the same time that power source mode changes to on (ACC).

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

GO TO IMMOBILISER SYSTEM (PROBLEM SYMPTOMS TABLE)

11.	INSPECT TRANSMITTER BATTERY

(a) Inspect the transmitter battery (See page ).

NOTICE:

Do not wrap the lead wire around a terminal, wedge it between terminals, or solder it. The terminal may be deformed or damaged, and the transmitter battery will not be able to be installed correctly.

OK

REPLACE ELECTRICAL KEY TRANSMITTER SUB-ASSEMBLY

NG

REPLACE TRANSMITTER BATTERY

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: Body Electrical / Starting Control / Data List.

(e) Read the Data List according to the display on the Techstream.

(f) Get into the vehicle while carrying the electrical key transmitter sub-assembly, move the shift lever to P, press the engine switch while depressing the brake pedal and confirm that the Techstream display changes.

Starting Control

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Starter SW	Starter operation request/ON or OFF	ON: Starter operation requested OFF: Starter operation not requested	When malfunctioning, the engine will not crank.

OK:

The Techstream display changes.

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

OK

13.	INSPECT ST RELAY (STARTER RELAY ASSEMBLY)

(a) Inspect the ST relay (starter relay assembly) (See page ).

NG

REPLACE ST RELAY (STARTER RELAY ASSEMBLY)

OK

14.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - BODY GROUND)

(a) Disconnect the C27 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the E13 ECM connector.

(c) Move the shift lever to P or N.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C27-10 (STAR) - Body ground	20°C (68°F)	107.05 to 116.33 Ω
C27-12 (STA) - Body ground	20°C (68°F)	106.78 to 115.98 Ω

Text in Illustration

*a	Front view of wire harness connector (to Certification ECU (Smart Key ECU Assembly))

NG

GO TO STEP 17

OK

15.	INSPECT STARTER ASSEMBLY

(a) Remove the starter assembly (See page ).

(b) Inspect the starter assembly (See page ).

NG

REPLACE STARTER ASSEMBLY

OK

16.	CHECK HARNESS AND CONNECTOR (BATTERY - STARTER ASSEMBLY AND ST RELAY (STARTER RELAY ASSEMBLY))

(a) Disconnect the S5 and S6 starter assembly connectors.

(b) Remove the ST relay (starter relay assembly) from the engine room relay block assembly.

(c) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition S5-1 - Body ground Always 11 to 14 V 5 (ST relay (starter relay assembly)) - Body ground Always 11 to 14 V

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
3 (ST relay (starter relay assembly)) - S6-1	Always	Below 1 Ω
3 (ST relay (starter relay assembly)) or S6-1 - Body ground	Always	10 kΩ or higher

Text in Illustration

*a	Engine Room Relay Block
*b	ST Relay (Starter Relay Assembly) Holder

OK

USE SIMULATION METHOD TO CHECK

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Disconnect the C27 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the P1 park/neutral position switch connector.

(c) Disconnect the E13 ECM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C27-10 (STAR) - P1-4 (B)	Always	Below 1 Ω
C27-10 (STAR) or P1-4 (B) - Body ground	Always	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

18.	CHECK HARNESS AND CONNECTOR (PARK/NEUTRAL POSITION SWITCH - ST RELAY (STARTER RELAY ASSEMBLY))

(a) Disconnect the P1 park/neutral position switch connector.

(b) Remove the ST relay (starter relay assembly) from the engine room relay block assembly.

(c) Disconnect the E13 ECM connector.

(d) Disconnect the C27 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
P1-5 (L) - 1 (ST relay (starter relay assembly))	Always	Below 1 Ω
P1-5 (L) or 1 (ST relay (starter relay assembly)) - Body ground	Always	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

19.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - ST RELAY (STARTER RELAY ASSEMBLY))

(a) Disconnect the C27 certification ECU (smart key ECU assembly) connector.

(b) Remove the ST relay (starter relay assembly) from the engine room relay block assembly.

(c) Disconnect the E13 ECM connector.

(d) Disconnect the P1 park/neutral position switch connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C27-12 (STA) - 1 (ST relay (starter relay assembly))	Always	Below 1 Ω
C27-12 (STA) or 1 (ST relay (starter relay assembly)) - Body ground	Always	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

20.	CHECK HARNESS AND CONNECTOR (ST RELAY (STARTER RELAY ASSEMBLY - BODY GROUND))

(a) Remove the ST relay (starter relay assembly) from the engine room relay 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 (starter relay assembly)) - Body ground	Always	Below 1 Ω

OK

USE SIMULATION METHOD TO CHECK

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

21.	CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) - STOP LIGHT SWITCH ASSEMBLY)

(a) Disconnect the C27 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the S10 stop light switch assembly connector.

(c) Disconnect the E13 ECM connector.

(d) Disconnect the S7 transmission floor shift assembly connector.

(e) Disconnect the S1 skid control ECU (brake actuator assembly) connector.

(f) Disconnect the R38 rear combination light assembly LH connector.

(g) Disconnect the R39 rear combination light assembly RH connector.

(h) Disconnect the C15 center stop light assembly connector.

(i) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition S10-2 - Body ground Always 11 to 14 V Text in Illustration *a Front view of wire harness connector (to Stop Light Switch Assembly)

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C27-2 (STP1) - S10-1	Always	Below 1 Ω
C27-2 (STP1) or S10-1 - Body ground	Always	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

22.	INSPECT STOP LIGHT SWITCH ASSEMBLY

(a) Inspect the stop light switch assembly (See page ).

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPLACE STOP LIGHT SWITCH ASSEMBLY

23.	INSPECT PARK/NEUTRAL POSITION SWITCH

(a) Remove the park/neutral position switch.

for AC60E: (See page )

for AC60F: (See page )

(b) Inspect the park/neutral position switch.

for AC60E: (See page )

for AC60F: (See page )

Result

Result	Proceed to
OK	A
NG (for AC60E)	B
NG (for AC60F)	C

B

REPLACE PARK/NEUTRAL POSITION SWITCH

C

REPLACE PARK/NEUTRAL POSITION SWITCH

A

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

(a) Disconnect the C27 certification ECU (smart key ECU assembly) connector.

(b) Disconnect the P1 park/neutral position switch connector.

(c) Disconnect the E13 ECM connector.

(d) Remove the ST relay (starter relay assembly) from the engine room relay block assembly.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C27-10 (STAR) - P1-4 (B)	Always	Below 1 Ω
C27-10 (STAR) or P1-4 (B) - Body ground	Always	10 kΩ or higher

OK

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR