Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 50

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

6E–195

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

Vehicle Speed Sensor Input Signal Frequency Too 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 P0500 (Symptom Code A) 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 A) 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 9

Go to Step 7

6

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

—

Go to Step 8

Go to Step 7

6E–196

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

7

Using the DVM and check the VSS signal.

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

2. Measure the VSS output voltage at sensor, 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 

9

Refer the table

8

Replace the VSS. 
Is the action complete?

—

Verify repair

9

Check any accessory parts which may cause electric
interference or magnetic interference. 
Was the problem found?

—

Remove the 

accessory parts 
and verify repair

Go to Step 11

10

Replace the speed meter. 
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

Step

Action

Value(s)

Yes

No

Measurement Position

Voltage (V) 

(AC Range)

If No 

Good

VSS terminal 3 & GND

Approximately 6.5 

V at 20km/h

Go to 

Step 8

Meter B23 connector 9 & 
GND

Go to 

Step 9

Meter B23 connector 8 & 
GND

Go to 

Step 10

ECM C56 connector 68 & 
GND

Go to 

Step 9

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

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

6E–197

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–198

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

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 16

Go to Step 7

6

Check for poor/faulty connection at the VSS 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

8

B-23

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