Isuzu KB P190. Manual - part 850

Engine Management – V6 – Diagnostics 

Page 6C1-2–122 

 

P0158, P0159, P0160, P0161, P0221, P0222, P0223, P0300, P0301-P0306, P0443, P0458, P0459, P0496, 
P167A, P167B, P2096, P2097, P2098, P2099, P2100, P2101, P2107, P2119, P2122, P2123, P2127, P2128, 
P2138, P2176, P2177, P2178, P2179, P2180, P2187, P2188, P2189, P2190, P2195, P2196, P2197, P2198, 
P2232, P2235, P2237, P2240, P2243, P2247, P2251, P2254, P2270, P2271, P2272, P2273, P2297, P2298, 
P2626, and P2629. 

• 

The engine speed is 1,040 – 3,000 rpm.  

• 

The air flow into the engine is between 7.0 – 16.0 g/s and not changing more than 3.0 g/s  

• 

The engine intake air temperature (IAT) at engine start-up is more than –30° C.  

• 

The engine is operating for more than 7 minutes.  

• 

The engine is operating in Closed Loop.  

• 

The calculated TWC temperature is between 500 – 750° C and steady.  

• 

The above conditions exist for approximately 17 minutes.  

• 

DTCs P0420 and P0430 run once a drive cycle. The ECM will attempt to run this diagnostic up to three times a 
drive cycle.  

Conditions for Setting the DTC 

The ECM determines that the catalyst efficiency has degraded below a calibrated threshold for more than 4 seconds. 

Action Taken When the DTC Sets 

• 

The control module activates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that 
the diagnostic runs and fails.  

• 

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic 
fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the 
second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. 
The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.  

Conditions for Clearing the DTC 

The EVAP Purge Solenoid Valve Control Circuit DTCs are Type B DTCs. Refer to 1.4 

Diagnostic Trouble Codes in 

this Section, for action taken when a Type B DTC sets and conditions for clearing Type B DTCs. 

P0420 or P0430 Diagnostic Table 

Step Action 

Yes 

No 

1 

Has the Diagnostic System Check been completed? 

Go to Step 2 

Refer to 

4.4 Diagnostic 
System Check in 

this Section 

2 

Are any other DTCs set? 

Go to the 

appropriate DTC 

Table in this Section 

Go to Step 3 

3 

1 

Inspect for the following conditions: 

• 

The catalytic converter is an original equipment part. 

• 

Inspect the exhaust system for leaks, damage, loose or 
missing hardware in the area from the converter to the 
heated oxygen sensor 2. 

• 

The HO2S 2 is secure and the wiring is not damaged or 
contacting the exhaust. 

Did you find and correct the condition? 

Go to Step 5 

Go to Step 4 

Engine Management – V6 – Diagnostics 

Page 6C1-2–123 

 

Step Action 

Yes 

No 

4 

N O T E  

Before replacing the 3-way catalytic converter (TWC), 
correct any conditions that may have damaged the 
converter. 

1 

Replace the catalytic converter. Refer to the appropriate 
procedure in 6F Exhaust System – V6. 

Did you complete the replacement? 

Go to Step 5 

— 

5 

1 

Using Tech 2, clear the DTC/s. 

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 EVAP purge solenoid valve control circuit DTCs fail 
this ignition cycle? 

Go to Step 2 

Go to Step 6 

6 

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, clear all DTCs and verify correct operation 

7.24  DTC P0443, P0458 or P0459 

DTC Descriptors 

This diagnostic procedure supports the following DTCs: 

• 

DTC P0443 – Evaporative Emission Control System Purge Solenoid Circuit Malfunction 

• 

DTC P0458 – Evaporative Emission Control System Purge Solenoid Circuit Low Voltage 

• 

DTC P0459 – Evaporative Emission Control System Purge Solenoid Circuit High Voltage 

Circuit Description 

The Engine control relay applies ignition positive battery voltage to the evaporative emission (EVAP) purge solenoid. 

Using a device called a driver, the ECM applies a pulse width modulated (PWM) ground to the EVAP solenoid control 
circuit to purge the fuel vapour from the EVAP canister into the intake manifold. 

The driver has a feedback circuit that is pulled-up to a voltage. The ECM monitors the driver feedback circuit to 
determine if the control circuit is open, shorted to ground or shorted to a positive voltage. 

An EVAP purge solenoid valve control circuit DTC sets if the ECM detects the voltage on the EVAP solenoid control 
circuit outside the predetermined range when the solenoid is commanded off. 

Conditions for Running the DTC 

DTC P0443 and P0458 

Runs continuously once the following conditions are met: 

• 

The engine speed is greater than 80 rpm 

• 

The ignition voltage is 10.0 – 16.0 V. 

• 

The ECM has commanded the EVAP Purge Solenoid Valve on and off at least once during the ignition cycle. 

DTC P0459 

Runs continuously once the following conditions are met: 

Engine Management – V6 – Diagnostics 

Page 6C1-2–124 

 

• 

The engine speed is greater than 80 rpm 

• 

The ignition voltage is 10.0 – 16.0 V. 

• 

The fuel system is in closed loop. 

• 

The engine speed is above idle. 

• 

The engine is at operating temperature. 

• 

The ECM has commanded the EVAP Purge Solenoid Valve on and off with a duty cycle of greater than 2.5%. 

Conditions for Setting the DTC 

DTC P0443 

The ECM detects the voltage on the EVAP solenoid control circuit is not within the predetermined range when the 
solenoid is commanded off. 

DTC P0458 

The ECM detects the voltage on the EVAP solenoid control circuit is less than 2.6 V when the solenoid is commanded 
off. 

DTC P0459 

The ECM detects the voltage on the EVAP solenoid control circuit is greater than 4.6 V when the solenoid is 
commanded on. 

Conditions for Clearing the DTC 

The EVAP Purge Solenoid Valve Control Circuit DTCs are Type B DTCs. Refer to 1.4 

Diagnostic Trouble Codes in 

this Section, for action taken when a Type B DTC sets and conditions for clearing Type B DTCs. 

Additional Information 

• 

Refer to 6C1-1 Engine Management – V6 – General Information for details of the EVAP Purge Solenoid Valve 
operation. 

• 

For an intermittent fault condition, refer to 5.2 

Intermittent Fault Conditions in this Section. 

• 

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. 

• 

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 number in the diagnostic table: 

4 

Tests the feedback voltage from the ECM. 

DTC P0443, P0458 or P0459 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 

Engine Management – V6 – Diagnostics 

Page 6C1-2–125 

 

Step Action 

Yes 

No 

2 

1 

Switch off the ignition for 30 seconds. 

2 

Allow the engine to reach the normal operating temperature or 
operate the vehicle within the conditions for running the DTC. 

3 

Using Tech 2, select the DTC display function. 

Does DTC P0443, P0458 or P0459 fail this ignition cycle? 

Go to Step 3 

Refer to Additional 

Information in this 

DTC 

3 

1 

Disconnect the EVAP solenoid valve wiring connector. 

2 

Switch on the ignition with the engine not running. 

3 

Connect a test lamp between the EVAP solenoid valve ignition 
voltage circuit and the ECM housing. 

Does the test lamp illuminate? 

Go to Step 4 

Go to Step 5 

4 

1 

Switch on the ignition with the engine not running. 

2 

Using a digital multimeter, measure the voltage between the 
EVAP solenoid valve control circuit and the ECM housing. 

Does the multimeter display 2.6 – 4.6 V? 

Go to Step 7 

Go to Step 6 

5 

Repair the high resistance, open circuit or short to ground fault 
condition at the EVAP solenoid valve ignition voltage circuit. Refer to 
8A Electrical - Body and Chassis for information on electrical wiring 
repair procedures 

Was the repair completed? 

Go to Step 9 

— 

6 

Test the control circuit of the EVAP solenoid valve for a high 
resistance, open circuit, short to ground or short to voltage fault 
condition. Refer to 8A Electrical - Body and Chassis for information on 
electrical fault diagnosis. 

Was any fault found and rectified? 

Go to Step 9 

Go to Step 8 

7 

Replace the EVAP solenoid valve. Refer to 6C1-3 Engine 
Management – V6 – Service Operations. 

Was the repair completed? 

Go to Step 9 

— 

8 

Replace the ECM. Refer to 6C1-3 Engine Management – V6 – 
Service Operations. 

Was the repair completed? 

Go to Step 9 

— 

9 

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 EVAP purge solenoid valve control circuit DTCs fail 
this ignition cycle? 

Go to Step 2 

Go to Step 10 

10  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. 

7.25  DTC P0460, P0461, P0462 or P0463 

DTC Descriptors 

This diagnostic procedure supports the following DTCs: 

• 

DTC P0460 – Fuel Level Sensor Range / Performance