Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual — part 152

6E–212

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

8

Using the DVM and check the A/C compressor relay
ground circuit.
Breaker box is available:

1. Ignition “Off”, engine “Off”.

2. Install the breaker box as type A. (ECM

disconnected)

3. Remove the A/C compressor relay from the relay

box.

4. Check the circuit for open or short to ground

circuit.

Was the problem found?

Breaker box is not available:

1. Ignition “Off”, engine “Off”.

2. Disconnect the ECM connector.

3. Remove the A/C compressor relay from the relay

box.

4. Check the circuit for open or short to ground

circuit.

Was the problem found?

—

Repair faulty
harness and

verify repair

Go to Step 9

9

Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

—

Verify repair

Go to Step 10

10

Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.

—

Verify repair

—

Step

Action

Value(s)

Yes

No

33

4

X-14

33

4

C-56

X-14

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–213

Diagnostic Trouble Code (DTC) P0645 (Symptom Code 8) (Flash Code 46) A/C

Compressor Relay Circuit Voltage High

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to Step 2

Go to On Board

Diagnostic

(OBD) System

Check

2

1. Connect the Tech 2.

2. Review and record the failure information.

3. Select “F0: Read DTC Infor As Stored By ECU” in

“F0: Diagnostic Trouble Codes”.

Is the DTC P0645 (Symptom Code 8) stored as
“Present Failure”?

—

Go to Step 3

Refer to

Diagnostic Aids

and Go to Step

3

3

1. Using the Tech 2, ignition “On” and engine “Off”.

2. Select “F1: Clear DTC Information” in “F0:

Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.

3. Operate the vehicle and monitor the “F0: Read

DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.

Was the DTC P0645 (Symptom Code 8) stored in this
ignition cycle?

—

Go to Step 4

Refer to

Diagnostic Aids

4

Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?

—

Verify repair

Go to Step 5

5

Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.

—

Go to Step 6

—

6

Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobiliser system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobiliser System-ECM replacement” for
the ECM/Immobiliser linking procedure.

—

Verify repair

—

6E–214

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

DIAGNOSTIC TROUBLE CODE (DTC) P0703 (SYMPTOM CODE A)

(FLASH CODE 25) BRAKE SWITCH INCORRECT SIGNAL (1)

DIAGNOSTIC TROUBLE CODE (DTC) P0703 (SYMPTOM CODE B)

(FLASH CODE 25) BRAKE SWITCH INCORRECT SIGNAL (2)

Battery
Voltage

Battery
Voltage

ECM
Main Relay

ECM
10A

Stop
15A

TCM

A / T

Injection
Pump

Stop
Lamp

IC

IC

CPU

0.5
BLU/
BLK

58

2.0
BLU/
RED

0.5
BLU/
RED

3

0.5
WHT/
BLK

65

0.85
RED

0.85
RED

0.85
GRN

30

0.5
BLU/
RED
63

0.5
YEL

31

0.5
BLK/
WHT

0.5
BLU/
RED

0.5
BLU/
RED

0.85
WHT

0.5
RED/
BLK

0.5
YEL/
VIO

Clutch
SW

Resister

Neutral
SW

87

0.5
BLU/
YEL

39

Brake
SW

M/T

A/T

Inhibitor
SW

Ignition
SW

Back up
15A

Engine
15A

µP

N

P

Engine
Control
Module
(ECM)

Batt

Batt

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–215

Condition for setting the DTC and action taken when the DTC sets

Circuit Description

The ECM monitors the brake switch signal on the feed
terminal to the ECM. If brake switch 1 or 2 circuit with
malfunction, DTC P0703 (Symptom Code A) or P0703
(Symptom Code B) will be stored.

Diagnostic Aids

An intermittent may be caused by the following:

• Poor connections.

• Misrouted harness.

• Rubbed through wire insulation.

• Broken wire inside the insulation.
Check for the following conditions:

• Poor connection at ECM-Inspect harness connectors

for backed out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal to wire connection.

• Damaged harness-Inspect the wiring harness for

damage. If the harness appears to be OK, observe
the “Brake Switch 1” and “Brake Switch 2” display on
the Tech2 while moving connectors and wiring
harness related to the sensor.

Diagnostic Trouble Code (DTC) P0703 (Symptom Code A) (Flash Code 25)

Brake Switch Malfunction

Flash

Code

Code

Symptom

Code

MIL

DTC Name

DTC Setting Condition

Fail-Safe (Back Up)

25

P0703

A

ON

Brake Switch Incorrect Signal
(1)

1. Throttle position is more

than 0%.

2. Engine speed is more than

665rpm.

3. Vehicle speed is more than

0km/h.

4. Brake switch 1 signal and

brake switch 2 signal are
differently inputted to the
ECM since the ignition
switch was turned on.

No fail-safe function.

B

ON

Brake Switch Incorrect Signal
(2)

1. Throttle position is more

than 0%.

2. Engine speed is more than

665rpm.

3. Vehicle speed is more than

0km/h.

4. Brake switch 1 signal and

brake switch 2 signal are
differently inputted to the
ECM.

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to Step 2

Go to On Board

Diagnostic

(OBD) System

Check

2

1. Connect the Tech 2.

2. Review and record the failure information.

3. Select “F0: Read DTC Infor As Stored By ECU” in

“F0: Diagnostic Trouble Codes”.

Is the DTC P0703 (Symptom Code A) stored as
“Present Failure”?

—

Go to Step 3

Refer to

Diagnostic Aids

and Go to Step

3