Isuzu KB P190. Manual - part 932

Powertrain Interface Module – V6 

Page 6E1–67 

 

10.3 Tachometer Diagnostics 

Circuit Description 

The powertrain interface module (PIM) receives the tachomer signal from the engine control module (ECM), it is then 
sent to the instrument cluster by the PIM via a hard wired connection to drive the tachometer which displays the engine 
RPM. Some of these components do not set a DTC, in the event of a component failure. The following diagnostic 
procedures are devised to assist in these cases. 

Additional Information 

• 

Refer to 7.2 Diagnostic System Check to monitor DTC’s. 

• 

Refer to 8A Electrical Body and Chassis for the following information: 

• 

ECM wiring diagram. 

• 

Refer to 6  Wiring Diagram and Connector Chart for the following information: 

• 

PIM connector illustration and terminal assignment, and 

• 

PIM wiring diagram. 

• 

For intermittent faults, refer to Intermittent Fault Conditions. 

• 

Check for an intermittent fault in the wiring harness or connectors, if a fault cannot be found the system is 
serviceable. 

Since fault conditions in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic 
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical - Body 
and Chassis for information on electrical fault diagnosis. 

Test Description 

The following numbers refer to the step numbers in the diagnostic table: 

1 

This step tests for DTC’s in the overall system. 

2 

This step uses the instrument cluster self test to check the function of the tachometer. 

3 

This step uses Tech 2 to drive the tachometer. 

6 

This step tests for tachometer drive frequency. 

10 

This step tests the in-vehicle function of the tachometer. 

Tachometer Diagnostic Table 

Step Action 

Yes 

No 

1 

Has the Diagnostic System Check been performed? 

 

Go to Step 2 

Refer to 

Additional 

Information 

2 

Test the function of the tachometer using the instrument cluster self  
diagnostic test procedure, refer to 8A Electrical Body and Chassis. 

Does the tachometer display 3000 RPM? 

Go to Step 3 

Go to Step 7 

3 

1 

Using Tech 2 select, 
 
Body / PIM / Miscellaneous Tests / Gauge Control Tests / 
Tachometer. 

2 

Using the Tech 2 soft keys step the tacho through different RPM 
ranges. 

Does the tachometer respond to the Tech 2 commands? 

Go to Step 5 

Go to Step 4 

Powertrain Interface Module – V6 

Page 6E1–68 

 

4 

Test for high resistance, open circuit, a short to ground of the relevant 
circuits from the PIM to the instrument cluster. Refer to 6 

Wiring 

Diagram and Connector Chart. 

Was any fault found and rectified? 

Go to Step 10 

Go to Step 5 

5 

Turn the ignition to the ON position, test for a short to voltage of the 
relevant circuits from the PIM to the instrument cluster. Refer to 6
 

Wiring Diagram and Connector Chart. 

Was any fault found and rectified? 

Go to Step 10 

Go to Step 6 

6 

Measure the frequency at the tachometer signal output from the ECM, 
refer to 8A Electrical Body and Chassis. 

Is the tachometer frequency present? 

Go to Step 7 

Refer to 
6C1-2 Engine 

Management 

Diagnostics

7 

Replace the PIM. 

Has the repair been completed? 

Go to Step 10 

— 

8 

Test the following instrument cluster circuits for a high resistance, 

open circuit or short to ground fault condition: 

• 

all 12 V battery supply circuits 

• 

all instrument cluster ground connections 

Was any fault found and rectified? 

Go to Step 10 

Go to Step 9 

9 

Replace the instrument cluster. 

Has the repair been completed? 

Go to Step 10 

— 

10  Start the vehicles engine. 

Does the tachometer function normally? 

System OK 

Go to Step 2 

When all diagnosis and repairs are completed, clear all DTCs and check the system for correct operation. 

Powertrain Interface Module – V6 

Page 6E1–69 

 

10.4 Temperature Gauge Diagnostics 

Circuit Description 

The powertrain interface module (PIM) receives engine temperature status via the GM Lan serial data bus from the 
engine control module (ECM) it is then sent to the instrument cluster by the PIM via a hard wired connection to drive the 
temperature gauge to the appropriate position. Some of these components do not set a DTC, in the event of a 
component failure. The following diagnostic procedures are devised to assist in these cases. 

Additional Information 

• 

Refer to 7.2 Diagnostic System Check to monitor DTC’s. 

• 

Refer to 8A Electrical Body and Chassis for the following information: 

• 

ECM wiring diagram. 

• 

Refer to 6  Wiring Diagram and Connector Chart for the following information: 

• 

PIM connector illustration and terminal assignment, and 

• 

PIM wiring diagram. 

• 

For intermittent faults, refer to Intermittent Fault Conditions. 

• 

Check for an intermittent fault in the wiring harness or connectors, if a fault cannot be found the system is 
serviceable. 

Since fault conditions in a wiring connector may trigger DTCs, always test the connectors related to this diagnostic 
procedure for shorted terminals or poor wiring connection before replacing any component. Refer to 8A Electrical - Body 
and Chassis for information on electrical fault diagnosis. 

Test Description 

The following numbers refer to the step numbers in the diagnostic table: 

1 

This step tests for DTC’s in the overall system. 

2 

This step uses the instrument cluster self test to check the function of the temperature gauge. 

3 

This step uses Tech 2 to drive the temperature gauge. 

6 

This step tests for set DTC’s in the ECM. 

11 

This step tests the in-vehicle function of the temperature gauge. 

Powertrain Interface Module – V6 

Page 6E1–70 

 

Temperature Gauge Diagnostic Table 

Step Action 

Yes 

No 

1 

Has the Diagnostic System Check been performed? 

 

Go to Step 2 

Refer to 

Additional 

Information 

2 

Test the function of the temperature gauge using the instrument 
cluster self diagnostic test procedure, refer to 8A Electrical Body and 
Chassis. 

Does the temperature gauge display a mid point reading on the dial?

Go to Step 3 

Go to Step 9 

3 

1 

Using Tech 2 select, 
 
Body / PIM / Miscellaneous Tests / Gauge Control Tests / 
Temperature Gauge. 

2 

Using the Tech 2 soft keys step the temperature gauge through 
the different ranges. 

Does the temperature gauge respond to the Tech 2 commands? 

Go to Step 6 

Go to Step 4 

4 

Test for high resistance, open circuit, a short to ground of the relevant 
circuits from the PIM to the instrument cluster. Refer to 6 

Wiring 

Diagram and Connector Chart. 

Was any fault found and rectified? 

Go to Step 11 

Go to Step 5 

5 

Turn the ignition to the ON position, test for a short to voltage of the 
relevant circuits from the PIM to the instrument cluster. Refer to 6
 

Wiring Diagram and Connector Chart. 

Was any fault found and rectified? 

Go to Step 11 

Go to Step 6 

6 

Using Tech 2 select, 

 
Body / ECM / Diagnostic Trouble Codes. 

Are any DTC’s set that will effect the operation of the temperature 
gauge? 

Go to Step 7 

Go to Step 8 

7 

Was any fault found and rectified? 

Go to Step 11 

— 

8 

Replace the PIM. 

Has the repair been completed? 

Go to Step 11 

— 

9 

Test the following instrument cluster circuits for a high resistance, 
open circuit or short to ground fault condition: 

• 

all 12 V battery supply circuits 

• 

all instrument cluster ground connections 

Was any fault found and rectified? 

Go to Step 11 

Go to Step 10 

10  Replace the instrument cluster. 

Has the repair been completed? 

Go to Step 11 

— 

11  Start the vehicles engine. 

Does the temperature gauge function normally? 

System OK 

Go to Step 2 

When all diagnosis and repairs are completed, clear all DTCs and check the system for correct operation.