Isuzu KB P190. Manual - part 875

Engine Management – V6 – Diagnostics 

Page 6C1-2–222 

 

• 

The ignition voltage is 10.0 – 16.0 V. 

Conditions for Setting the DTC 

The ECM did not receive a valid signal from the PIM within the specified time frame. 

Conditions for Clearing the DTC 

The PIM serial data communication circuit DTCs are Type C DTCs. Refer to 1.4  Diagnostic Trouble Codes in this 
Section, for action taken when a Type C DTC sets and conditions for clearing Type C DTCs. 

Additional Information 

• 

Refer to 6C1-1 Engine Management – V6 – General Information for details of the ECM operation. 

• 

Since fault condition 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. 

• 

For an intermittent fault condition, refer to 5.2 

Intermittent Fault Conditions in this Section. 

• 

To assist diagnosis, refer to 3 

Wiring Diagrams and Connector Charts in this Section, for the system wiring 

diagram and connector charts. 

Test Description 

The following number refers to the step numbers in the diagnostic table: 

1 

The following tests are included in the Diagnostic System Check. 

• 

Tests the integrity of the GM LAN serial data communication circuit.  

• 

Tests for fault conditions on the vehicle immobiliser system stored in the ICU. 

DTC U0155 or U0423 Diagnostic Table 

Step Action 

Yes 

No 

1 

Has the Diagnostic System Check been performed? 

Go to Step 2 

Refer to 

4.4 Diagnostic 
System Check in 

this Section 

2 

1 

Switch off the ignition for 30 seconds. 

2 

Operate the vehicle within the conditions for running the DTC. 

3 

Using Tech 2, select the DTC display function. 

Does DTC U0155, or U0423 fail this ignition cycle? 

Go to Step 3 

Refer to Additional 

Information in this 

Section 

3 

Replace the PIM. Refer to 6E1 Powertrain Interface Module – V6. 

Was the repair completed? 

Go to Step 4 

— 

4 

1 

Using Tech 2, clear the DTCs. 

2 

Switch off the ignition for 30 seconds. 

3 

Start the engine. 

4 

Operate the vehicle within the conditions for running the DTC. 

Does any of the PIM serial data communication circuit DTCs fail this 
ignition cycle? 

Go to Step 2 

Go to Step 5 

5 

Using Tech 2, select the DTC display function. 

Does Tech 2 display any DTCs? 

Go to the 

appropriate DTC 

Table in this Section 

System OK 

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

Engine Management – V6 – Diagnostics 

Page 6C1-2–223 

 

8 

HFV6 Engine – Tech 2 Functions 

8.1 Introduction 

 

Do not use a Tech 2 that displays faulty data; 
have the Tech 2 repaired. The use of a faulty 
Tech 2 can result in misdiagnosis and the 
unnecessary replacement of parts. 

From the Main Menu, having selected Diagnostics / 2006 / RA Rodeo / Engine, the Tech 2 functions for the HFV6 
engine, include: 

F0:  Diagnostic Trouble Codes 

F1: Data 

Display 

F2: OBD 

Data 

F3: Snapshot 

F4: Actuator 

Test 

F5: Additional 

Functions 

F6: Programming 

8.2 

Tech 2 Functions 

F0:  Diagnostic Trouble Codes 

When this test mode is initiated, DTCs stored by the ECM can be displayed or cleared. When entered, there are three 
additional modes for selection: 

F0:  Read DTC Information:  All DTCs stored in the ECM will be displayed. 

F1:  Clear Engine & Transmission DTCs:  Clears all current DTCs in the ECM and TCM memories. 

F2:  Freeze Frame/Failure Records:  Shows the Freeze Frame information. Freeze Frames are types of snapshots 

stored in the ECM memory. 

F1: Data 

Display 

• 

Use the Tech 2 Data List under the following conditions: 

• 

The Diagnostic System Check – HFV6 Engine has been completed. 

• 

The On-Board Diagnostics are functioning correctly. 

• 

No DTCs are present. 

N O T E  

•  Tech 2 values from an engine that is 

operating correctly may be used for 
comparison with the engine you are 
diagnosing. The Tech 2 engine data lists 
represent typical values that would be seen 
on a normal operating engine. 

•  The Tech 2 Data Definitions list that follows 

the Data Lists, is arranged in alphabetical 
order and contains a brief description of all of 
the engine related parameters that are 
available. 

The following ‘typical’ Tech 2 values were recorded under the following conditions: 

Engine Management – V6 – Diagnostics 

Page 6C1-2–224 

 

Ignition ON: 

• 

Engine stopped, ignition in the ON position. 

• 

Closed throttle. 

• 

Transmission selector in the Park position (Automatic 
Transmission) or Neutral (Manual Transmission. 

• 

Engine, transmission at ambient temperature. 

• 

Accessories are OFF. 

• 

Brake pedal is not applied. 

Engine Running 

• 

Engine running. 

• 

Closed throttle. 

• 

Transmission selector in the Park position (Automatic 
Transmission) or Neutral (Manual Transmission. 

• 

Engine, transmission at normal operating temperature.

• 

Accessories are OFF. 

• 

Brake pedal not applied. 

N O T E  

The values quoted in the following data lists are 
only intended to provide the Technician with an 
indication of the values to be expected. 

When ‘F1 Data Display’ is selected, there are 12 data lists provided, that can save time when diagnosing symptomatic 
conditions. 

Engine Data 1 

Engine Data 2 

EVAP Data 

Fuel Trim Data 

O2 Sensor Data 

TAC Data (Throttle Actuator Control) 

Cooling/HVAC Data 

Cruise Control Data 

Electrical/Theft Data 

Instrument Data 

ODM Data (Output Driver Module) 

Misfire Data 

F2: OBD 

Data 

In this test mode, Tech 2 displays engine management data parameters relating to the OBD (On Board Diagnostic) for 
the engine being diagnosed. Refer to 8.5 

OBD Data for specific detail. 

F3: Snapshot 

In this test mode, Tech 2 captures data before and after a snapshot triggering event that may or may not set a DTC.  

F4: Actuator 

Test 

In this test mode, Tech 2 performs software override commands to the ECM, to assist in problem isolation during 
diagnostics. When entering this mode, there are 9 actuators that can be tested for operational integrity. The 9 tests 
available are: 

F0:    Fuel Pump Relay Test 

F1:    Electronic Throttle Control Test 

F2:    A/C Relay Test 

F3:     Cooling Fan PWM 

F4:    Alternator L Terminal 

Engine Management – V6 – Diagnostics 

Page 6C1-2–225 

 

F5:    EVAP Purge Solenoid 

F6:    Engine Speed Control 

F7:    Starter Relay Test 

F8:    Fuel Injector Balance 

F5: Additional 

Functions 

When this selection is made from the Tech 2 screen, an additional two choices are provided: 

F0:  System Identification: In this mode, Tech 2 will display the engine identification screen. 

F1:  Security Information: When selected, this mode displays various engine management data parameters relating to 

the security system. 

F6: Programming 

Within this selection, there are five programming selections available: 

F0:    Immobiliser Link to ECM/PIM 

F1: Reset 

ECU 

F2:  Fuel Trim Reset 

F3:  Reset Engine Oil Life 

F4:    Throttle Body Relearn