Toyota FJ Cruiser (GSJ 10, 15 series). Instruction - part 273

INTRODUCTION  –  HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS

IN–47

IN

(b) Check the resistance.

(1) Disconnect connectors A and C and measure 

the resistance between them.
Standard resistance (Fig. 2)

HINT:
Measure the resistance while lightly shaking the 
wire harness vertically and horizontally. If the 
results match the examples above, an open 
circuit exists between terminal 1 of connector A 
and terminal 1 of connector C.

(2) Disconnect connector B and measure the 

resistance between the connectors.
Standard resistance (Fig. 3)

If the results match the examples above, an 
open circuit exists between terminal 1 of 
connector B2 and terminal 1 of connector C.

(c) Check the voltage.

(1) In a circuit in which voltage is applied to the ECU 

connector terminal, an open circuit can be 
checked by conducting a voltage check.
With each connector still connected, measure 
the voltage between the body ground and these 
terminals (in this order): 1) terminal 1 of 
connector A, 2) terminal 1 of connector B, and 3) 
terminal 1 of connector C.
Standard voltage (Fig. 4)

If the results match the examples above, an 
open circuit exists in the wire harness between 
terminal 1 of connector B and terminal 1 of 
connector C.

Fig. 2

ECU

B

SENSOR

A

C

1

2

2

2

1

1

Z017005E02

Tester Connection

Specified Condition

Connector A terminal 1 - Connector 
C terminal 1

10 k

Ω or higher

Connector A terminal 2 - Connector 
C terminal 2

Below 1

Ω

Fig. 3

ECU

B2

SENSOR

C

1

2

2

2

2

1

1

1

B1

A

B004722E03

Tester Connection

Specified Condition

Connector A terminal 1 - Connector 
B1 terminal 1

Below 1 

Ω

Connector B2 terminal 1 - Connector 
C terminal 1

10 k

Ω or higher

Fig. 4

0 V

ECU

B

SENSOR

A

C

1

2

2

2

2

1

1

5 V

5 V

Z017007E02

Tester Connection

Specified Condition

Connector A terminal 1 - Body 
ground

5 V

Connector B terminal 1 - Body 
ground

5 V

Connector C terminal 1 - Body 
ground

Below 1 V

IN–48

INTRODUCTION  –  HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS

IN

3.

CHECK FOR SHORT CIRCUIT
(a) If the wire harness is ground shorted (Fig. 5), locate 

the section by conducting a resistance check with 
the body ground (below).

(b) Check the resistance with the body ground.

(1) Disconnect connectors A and C and measure 

the resistance.
Standard resistance (Fig. 6)

HINT:
Measure the resistance while lightly shaking the 
wire harness vertically and horizontally. If your 
results match the examples above, a short 
circuit exists between terminal 1 of connector A 
and terminal 1 of connector C.

(2) Disconnect connector B and measure the 

resistance.
Standard resistance (Fig. 7)

If the results match the examples above, a short 
circuit exists between terminal 1 of connector B2 
and terminal 1 of connector C.

4.

CHECK AND REPLACE ECU
NOTICE:
•

The connector should not be disconnected from 
the ECU. Perform the inspection from the 
backside of the connector on the wire harness 
side.

•

When no measuring condition is specified, 
perform the inspection with the engine stopped 
and the ignition switch ON.

•

Check that the connectors are fully seated. Check 
for loose, corroded or broken wires.

Fig. 5

ECU

B

SHORT

A

C

1

2

2

2

1

1

Z017008E02

Fig. 6

ECU

B

SENSOR

A

C

1

2

2

2

1

1

Z017009E02

Tester Connection

Specified Condition

Connector A terminal 1 - Body 
ground

Below 1 

Ω

Connector A terminal 2 - Body 
ground

10 k

Ω or higher

Fig. 7

ECU

B1

SENSOR

A

C

1

2

2

2

1

1

B2

2

1

Z017808E02

Tester Connection

Specified Condition

Connector A terminal 1 - Body 
ground

10 k

Ω or higher

Connector B2 terminal 1 - Body 
ground 

Below 1 

Ω

INTRODUCTION  –  HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS

IN–49

IN

(a) First, check the ECU ground circuit. If it is faulty, 

repair it. If it is normal, the ECU could be faulty. 
Temporarily replace the ECU with a normally 
functioning one and check if the symptoms occur. If 
the trouble symptoms disappear, replace the 
original ECU.
(1) Measure the resistance between the ECU 

ground terminal and body ground.
Standard resistance:

Below 1 

Ω

(2) Disconnect the ECU connector. Check the 

ground terminal on the ECU side and wire 
harness side for bending, corrosion or foreign 
matter. Lastly, check the contact pressure of the 
female terminals.

Example:

Ground

IN00383E02

W/H Side

ECU Side

Wire Harness Side

Ground

Ground

IN00384E03

IN–50

INTRODUCTION  –  TERMS

IN

TERMS

ABBREVIATIONS USED IN MANUAL

ABBREVIATIONS

MEANING

1st

First

2nd

Second

2WD

Two Wheel Drive Vehicle (4 x 2)

3rd

Third

4th

Fourth

4WD

Four Wheel Drive Vehicle (4 x 4)

4WS

Four Wheel Steering System

5th

Fifth

A.D.D.

Automatic Disconnecting Differential

A/C

Air Conditioner

A/F

Air-Fuel Ratio

A/T, ATM

Automatic Transmission (Transaxle)

ABS

Anti-Lock Brake System

AC

Alternating Current

ACC

Accessory

ACIS

Acoustic Control Induction System

ACM

Active Control Engine Mount

ACSD

Automatic Cold Start Device

AFS

Adaptive Front-Lighting System

AHC

Active Height Control Suspension

AID

Air Injection Control Driver

ALR

Automatic Locking Retractor

ALT

Alternator

AMP

Amplifier

ANT

Antenna

APPROX.

Approximately

ASSB

Assembly Services Sdn. Bhd.

ASSY

Assembly

ATF

Automatic Transmission Fluid

AUTO

Automatic

AUX

Auxiliary

AVG

Average

AVS

Adaptive Variable Suspension

B/L

Bi-Level

B/S

Bore-Stroke Ratio

B+

Battery Voltage

BA

Brake Assist

BACS

Boost Altitude Compensation System

BAT

Battery

BDC

Bottom Dead Center

BTDC

Before Top Dead Center

BVSV

Bimetallic Vacuum Switching Valve

C/V

Check Valve

Calif.

California

CAN

Controller Area Network

CB

Circuit Breaker