Toyota Tundra Service Manual: Terminals Of Ecu

TERMINALS OF ECU

1. CHECK COMBINATION METER

(a) Measure the voltage, resistance and waveform according to the value(s) in the table below.

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

*1: w/ Intuitive Parking Assist System

*2: w/ Towing Package

*3: The minimum voltage value varies depending on the +BS terminal voltage value. The minimum voltage is 85% or more of the +BS terminal voltage.

J28-1 (B) - Body ground

LG- Body ground

Power source

Always

11 to 14 V

J28-2 (IG+) - Body ground

B - Body ground

Ignitoin switch signal

Ignition switch off

Below 1 V

Ignition switch ON

11 to 14 V

J28-3 (BZ) - Body ground*1

V - Body ground

Clearance warning buzzer

Clearance warning buzzer sounding (when the back sonar senses something)

Pulse generation

J28-4 (BK) - Body ground*1

SB - Body ground

Ultrasonic sensor (for rear corner LH and RH)

Clearance warning indicator LED for back right and left illuminates

Below 3 V

J28-5 (OP) - Body ground*1

R - Body ground

Clearance warning ECU signal

Clearance warning indicator's operation indicator illuminates

Below 3 V

J28-6 (FR) - Body ground*1

W - Body ground

Ultrasonic sensor (for front corner RH)

Clearance warning indicator LED for front corner RH illuminates

Below 3 V

J28-7 (FL) - Body ground*1

LG - Body ground

Ultrasonic sensor (for front corner LH)

Clearance warning indicator LED for front corner LH illuminates

Below 3 V

J28-8 (RR) - Body ground*1

G - Body ground

Ultrasonic sensor (for rear corner RH)

Clearance warning indicator LED for rear corner RH illuminates

Below 3 V

J28-9 (RL) - Body ground*1

GR - Body ground

Ultrasonic sensor (for rear corner LH)

Clearance warning indicator LED for rear corner LH illuminates

Below 3 V

J28-10 (MSM+) - Body ground

P - Body ground

Steering pad switch signal

Ignition switch ON, enter, top and back switches on steering pad switch not pushed

4.3 to 5.2 V

Ignition switch ON, enter switch on steering pad switch pushed

Below 0.6 V

Ignition switch ON, top switch on steering pad switch pushed

1.0 to 2.2 V

Ignition switch ON, back switch on steering pad switch pushed

2.3 to 3.4 V

J28-11 (MSTI) - Body ground

L - Body ground

Steering pad switch signal

Ignition switch ON, up, wn, right and left switches on steering pad switch assembly not pushed

4.3 to 5.2 V

Ignition switch ON, left switch on steering pad switch pushed

Below 0.6 V

Ignition switch ON, up switch on steering pad switch pushed

1.0 to 2.2 V

Ignition switch ON, down switch on steering pad switch pushed

2.3 to 3.4 V

Ignition switch ON, right switch on steering pad switch pushed

3.4 to 4.5 V

J28-12 (MSSL) - Body ground

BE - Body ground

Ground

Always

Below 1 Ω

J28-13 (CHG-) - Body ground

B - Body ground

CHARGE warning light

Ignition switch ON, washer level warning light ON

Below 1 V

Ignition switch ON, washer level warning light OFF

11 to 14 V

J28-14 (SW) - Body ground

R - Body ground

Brake fluid level warning light signal

Ignition switch ON, BRAKE warning light ON

Below 1 V

Ignition switch ON, BRAKE warning light OFF

11 to 14 V

J28-15 (WLVL) - Body ground

SB - Body ground

Washer level warning light

Ignition switch ON, washer level warning light ON

Below 1 V

Ignition switch ON, washer level warning light OFF

11 to 14 V

J28-28 (EL) - Body ground

LG - Body ground

Turn signal L

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to left

Alternating between below 1V and 11 to 14 V

J28-17 (ER) - Body ground

G - Body ground

Turn signal R

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to right

Alternating between below 1V and 11 to 14 V

J28-18 (MSCH)

Y

CAN commuinication

-

-

J28-19 (MSCL)

W

CAN commuinication

-

-

J28-20 (HAZ) - Body ground

L - Body ground

Hazard warning signal switch signal (Output)

Hazard warning signal switch off

Below 1 V

Hazard warning signal switch on

Alternating between below 1V and 11 to 14 V

J28-22 (ILL-) - Body ground

BE - Body ground

Illumination signal

Headlight dimmer switch off

Below 1 V

Headlight dimmer switch in tail or head position

11 to 14 V

J28-23 (EP) - Body ground

W-B - Body ground

Illumination ground

Always

Below 1 Ω

J28-24 (ES) - Body ground

BR - Body ground

Ground

Always

Below 1 Ω

J28-25 (E3) - Body ground

Y - Body ground

Fuel sender gauge ground

Always

Below 1 Ω

J28-26 (L) - Body ground

V - Body ground

Fuel sender gauge

Ignition switch ON, fuel sender gauge ON

Below 1 V

Ignition switch ON, fuel sender gauge OFF

11 to 14 V

J28-27 (S) - Body ground

L - Body ground

Oil pressure warning light

Ignition switch ON, oil pressure warning light ON

Below 1 V

Ignition switch ON, oil pressure warning light OFF

11 to 14 V

J28-28 (SW) - Body ground

BE - Body ground

Turn signal switch signal

Ignition switch ON, LH and RH turn signal switch off

11 to 14 V

Ignition switch ON, LH or RH turn signal switch on

Below 1 V

J28-29 (+S) - Body ground

SB - Body ground

Speed signal (output)

Ignition switch ON, wheel turned slowly

Pulse generation

(See waveform 1)

J28-30 (SI) - Body ground

LG - Body ground

Speed signal for other system (Input)

Ignition switch ON, wheel being rotated

Pulse generation

(See waveform 1)

J28-31 (P) - Body ground

V - Body ground

A/T shift position signal P

Ignition switch ON, shift lever not in P

Below 1 V

Ignition switch ON, shift lever in P

11 to 14 V

J28-32 (R) - Body ground

R - Body ground

A/T shift position signal R

Ignition switch ON, shift lever not in R

Below 1 V

Ignition switch ON, shift lever in R

11 to 14 V

J28-33 (N) - Body ground

W - Body ground

A/T shift position signal N

Ignition switch ON, shift lever not in N

Below 1 V

Ignition switch ON, shift lever in N

11 to 14 V

J28-34 (D) - Body ground

L - Body ground

A/T shift position signal D

Ignition switch ON, shift lever not in D

Below 1 V

Ignition switch ON, shift lever in D

11 to 14 V

J28-35 (4) - Body ground

V - Body ground

A/T shift position signal S

Ignition switch ON, shift lever not in S

Below 1 V

Ignition switch ON, shift lever in S

11 to 14 V

J28-36 (LP) - Body ground

BE - Body ground

Security indicator light signal

Immobiliser set status (SET)

Alternating between 11 to 14 V and below 1 V

Immobiliser set status (UNSET)

Below 1 V

J28-38 (BKSW) - Body ground

R - Body ground

Stop light control relay (stop light switch assembly) input

Stop light switch assembly on → off (Brake pedal depressed → released)

(+BS x 0.85) to 14 V*3 → Below 1.5 V

J28-39 (CANH)

SB

CAN commuinication

-

-

J28-40 (CANL)

W

CAN commuinication

-

-

J171-1 (TRT) - Body ground*2

B - Body ground

Trailer socket signal RH signal

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to right

Alternating between below 1V and 11 to 14 V

J171-7 (TLT) - Body ground*2

Y - Body ground

Trailer socket signal LH signal

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to left

Alternating between below 1V and 11 to 14 V

J171-8 (B) - Body ground

V - Body ground

Power source

Always

11 to 14 V

J171-9 (LL) - Body ground

G - Body ground

Turn signal L

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to left

Alternating between below 1V and 11 to 14 V

J171-10 (LR) - Body ground

BE - Body ground

Turn signal R

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to right

Alternating between below 1V and 11 to 14 V

J171-11 (RLT) - Body ground

B - Body ground

Rear turn signal light LH signal

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to left

Alternating between below 1V and 11 to 14 V

J171-12 (RRT) - Body ground

SB - Body ground

Rear turn signal light RH signal

Ignition switch ON, turn signal switch neutral position

Below 1 V

Ignition switch ON, turn signal switch turned to right

Alternating between below 1V and 11 to 14 V

J171-13 (B) - Body ground

GR - Body ground

Power source

Always

11 to 14 V

(1) Waveform 1 (Reference):

Item

Condition

Tool setting

5 V/DIV., 20 ms./DIV.

Vehicle condition

Ignition switch ON, wheel turned slowly

HINT:

When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows.

2. CHECK COMBINATION METER INNER CIRCUIT

    Tachometer Malfunction

    Lost Communication with Front Camera Module (U023A)

    See More:

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