Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 142

6E–172

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0400 (Symptom Code 4) (Flash Code 32) 

Exhaust Gas Recirculation Circuit Short to Ground or Open Circuit

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 P0400 (Symptom Code 4) 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 P0400 (Symptom Code 4) stored in this
ignition cycle?

—

Go to Step 4

Refer to 

Diagnostic Aids 

and Go to Step 

4

4

Check for poor/faulty connection at the EGR EVRV 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 EGR EVRV.

1. Ignition “Off”,  engine “Off”. 

2. Disconnect the EGR EVRV connector. 

3. Measure the resistance of EGR EVRV solenoid

coil. 

Does the tester indicate standard resistance? 

Approximately 

14

Ω at 20°C

Go  to  Step 6

Go to Step 9

97

1

2

C-115

C-57

1

2

EGR EVRV

1

2

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–173

6

Using the DVM and check the EGR EVRV power
supply circuit. 

1. Ignition “On”, engine “Off”. 

2. Remove the EGR EVRV connector. 

3. Check the circuit for open circuit. 

Was the DVM indicated specified value?

Battery 
voltage

Go to Step 8

Go to Step 7

7

Repair the open circuit between the ECM main relay
and EGR EVRV. 
Is the action complete?

—

Verify repair

—

8

Using the DVM and check the EGR EVRV circuit. 
Breaker box is available: 

1. Ignition “Off”, engine “Off”. 

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

disconnected) Ref. Page 6E-73 

3. Remove the EGR EVRV connector. 

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 EGR EVRV connector. 

4. Check the circuit for open or short to ground

circuit. 

Was the problem found?

—

Repair faulty 
harness and 

verify repair

Go to Step 11

9

Substitute a known good EGR EVRV and recheck. 
Was the problem solved?

—

Go to Step 10

Go to Step 11

Step

Action

Value(s)

Yes

No

V

1

C-115

97

2

C-115

97

2

C-115

C-57

6E–174

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

10

Replace the EGR EVRV. 
Is the action complete?

—

Verify repair

—

11

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 12

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

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–175

Diagnostic Trouble Code (DTC) P0400 (Symptom Code 5) (Flash Code 32) 

Exhaust Gas Recirculation Flow Insufficient Detected

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 P0400 (Symptom Code 5) 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 P0400 (Symptom Code 5) stored in this
ignition cycle?

—

Go to Step 4

Refer to 

Diagnostic Aids 

and Go to Step 

4

4

Visually check the EGR control vacuum hose.
If the hose is clogged or disconnected, repair as
necessary. 
Was the problem found? 

—

Verify repair

Go to Step 5

5

Using the DVM and check the EGR EVRV.

1. Ignition “Off”,  engine “Off”. 

2. Disconnect the EGR EVRV connector. 

3. Measure the resistance of EGR EVRV solenoid

coil. 

Does the tester indicate standard resistance?   

Approximately 

14

Ω at 20°C

Go to Step 8

Go to Step 6

6

Substitute a known good EGR EVRV and recheck.
Was the problem solved?

—

Go to Step 7

Go to Step 8

7

Replace the EGR EVRV. 
Is the action complete?

—

Verify repair

—

1

2

EGR EVRV

1

2