Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 146

6E–188

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

13

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–189

Diagnostic Trouble Code (DTC) P0500 (Symptom Code B) (Flash Code 24) 

Vehicle Speed Sensor Incorrect Signal

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 P0500 (Symptom Code B) 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 P0500 (Symptom Code B) stored in this
ignition cycle?

—

Go to Step 4

Refer to 

Diagnostic Aids 

and Go to Step 

4

4

Perform test drive and check the speed meter. 
Does the speed meter indicate correct vehicle speed.

—

Go to Step 5

Go to Step 6

5

Perform test drive and use the Tech 2.  
Monitor the “Vehicle Speed” in the data display. 
Does the Tech 2 indicate correct vehicle speed as
same as the speed meter indication in the instrument
panel?

—

Go to Step 17

Go to Step 7

6

Check for poor/faulty connection at the VSS, TCM (A/
T 2WD) and meter connectors. If a poor/faulty
connection is found, repair the faulty terminal. 
Was the problem found?

—

Verify repair

Go to Step 8

1

3

2

9 10

10

B-24

C-94(10)

E-44

6E–190

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

7

Check for poor/faulty connection at the ECM and other
connectors. If a poor/faulty connection is found, repair
the faulty terminal. 
Was the problem found?

—

Verify repair

Go to Step 9

8

Remove the VSS from the housing case and visually
check. 
Was the problem found? 

—

Go to Step 10

Go to Step 9

9

Using the DVM and check the VSS signal.

1. Ignition “On”, vehicle “Run (lift up)”. 

2. Measure the VSS output voltage at sensor, TCM

(A/T 2WD), meter and ECM. 

Does the tester indicate specified value? 

If a oscilloscope is available, monitor the VSS signal at
each connector connection. Does the oscilloscope
indicate correct wave form? 

Refer to 

Diagnostic Aids 

and Go to Step 

17

Refer the table

10

Replace the VSS. 
Is the action complete?

—

Verify repair

Step

Action

Value(s)

Yes

No

68

C-56

Measurement Position

Voltage (V) 

(AC Range)

If No 

Good

VSS terminal 3 & GND

Approximately 6.5 

V at 20km/h

Go to 

Step 10

TCM C94 connector 10 & 
GND (A/T 2WD)

Go to 

Step 11

Meter B24 connector 9 & 
GND

Go to 

Step 12

Meter B24 connector 10 & 
GND

Go to 

Step 14

ECM C56 connector 68 & 
GND

Go to 

Step 15

Vehicle Speed Sensor Reference Wave Form

0V

→

Measurement Scale: 10V/div

50ms/div

Measurement Condition: Vehicle Speed 20km/h
Measurement Terminal: At Engine Control Module

4JH1 ENGINE DRIVEABILITY AND EMISSIONS

6E–191

11

Replace the TCM. 
Is the action complete? 
IMPORTANT: The replacement TCM must be
programmed. “SPS (Service Programming System)
is necessary.” 

—

Verify repair

—

12

Using the DVM and check the VSS signal circuit.

1. Ignition “On”, engine “Off”. 

2. Disconnect the meter connector. 

3. Check the circuit for short to power supply circuit. 

Was the DVM indicated specified value? 

Less than 1V

Go to Step 13

Repair faulty 
harness and 

verify repair

13

Using the DVM and check the VSS signal circuit.

1. Ignition “Off”, engine “Off”. 

2. Disconnect the VSS connector and meter

connector. 

3. Check the circuit for open or short to ground

circuit. 

If a open or short to ground circuit is found, repair the
faulty harness and verify repair. 
Is the action complete?

—

Verify repair

—

14

Replace the speed meter. 
Is the action complete?

—

Verify repair

—

Step

Action

Value(s)

Yes

No

9

V

B-24

3

9

E-44

B-24