Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 72

4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

6E–283

12

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

6E–284

4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P1577 (Symptom Code 8) (Flash Code 71) 

Exhaust Throttle VSV 2 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 P1577 (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 P1577 (Symptom Code 8) stored in this
ignition cycle?

—

Go to Step 4

Refer to 

Diagnostic Aids

4

Check for poor/faulty connection at the exhaust
throttle VSV 2 or ECM connector. If a poor/faulty
connection is found, repair as necessary. 
Was the problem found?

—

Verify repair

Go to Step 5

5

Using the DVM and check the exhaust throttle VSV 2.

1. Ignition “Off”,  engine “Off”. 

2. Disconnect the exhaust throttle VSV 2 connector. 

3. Measure the resistance of EGR EVRV solenoid

coil. 

Does the tester indicate standard resistance?  

Approximately 

40

Ω at 20°C

Go  to  Step 6

Go to Step 8

61

2

1

C-14

C-56

1

2

1

2

VSV-2

4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

6E–285

6

Using the DVM and check the exhaust throttle VSV 2
circuit. 

1. Ignition “Off”, engine “Off”. 

2. Remove the exhaust throttle VSV 2 connector and

ECM connector. 

3. Check the circuit for short to voltage circuit. 

Was the DVM indicated specified value?

No continuity

Go to Step 10

Go to Step 7

7

Repair the short to voltage circuit. 
Is the action complete?

—

Verify repair

—

8

Substitute a known good exhaust throttle VSV 2 and
recheck.                                                                                              
Was the problem solved?

—

Go to Step 9

Go to Step 10

9

Replace the exhaust throttle VSV 2. 
Is the action complete?

—

Verify repair

—

10

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 11

11

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

2

1

C-14

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4JA1-TC/4JH1-TC ENGINE DRIVEABILITY AND EMISSIONS

DIAGNOSTIC TROUBLE CODE (DTC) P1605 (SYMPTOM CODE D) 

(FLASH CODE 55) EEPROM DEFECT

DIAGNOSTIC TROUBLE CODE (DTC) P1605 (SYMPTOM CODE E) 

(FLASH CODE 55) EEPROM DEFECT

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

Circuit Description & Diagnostic Aids

The ECM used in this vehicle utilizes an electrically
erasable & programmable read only memory
(EEPROM). The EEPROM contains program
information and the calibrations required for engine and

diagnostics operation. 
If the ECM inside (IC, circuit, memory, etc,) failed, DTC
P1605 (Symptom Code C), P1605 (Symptom Code D)
or P1605 (Symptom Code E) will be stored.

Diagnostic Trouble Code (DTC) P1605 (Symptom Code D) (Flash Code 55) 

EEPROM Defect

Diagnostic Trouble Code (DTC) P1605 (Symptom Code E) (Flash Code 55) 

EEPROM Defect

Flash 

Code

Code

Symptom 

Code

MIL

DTC Name

DTC Setting Condition

Fail-Safe (Back Up)

55

P1605

D

ON

EEPROM Defect

Write and read from the 
EEPROM are failed during ini-
tialization of the ECM.

ECM uses default values from 
the EPROM.

E

ON

EEPROM Defect

EEPROM checksum does not 
match with the read check 
sum during initialization of 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 P1605 (Symptom Code D) or P1605
(Symptom Code E) 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 P1605 (Symptom Code D) or P1605
(Symptom Code E) 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