Circuit ISUZU KB P190 2007 Workshop Repair Manual

Engine Management – V6 – Diagnostics Page 6C1-2–123

Step Action Yes No
4 NOTE
Before replacing the 3-way catalytic converter (TW C),
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 (PW M) 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:

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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 W iring 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

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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
W as 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.
W as 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.
W as the repair completed? Go to Step 9 —
8 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as 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

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Engine Management – V6 – Diagnostics Page 6C1-2–126

• DTC P0461 – Fuel Level Sensor Range / Performance
• DTC P0462 – Fuel Level Sensor Low Voltage
• DTC P0463 – Fuel Level Sensor High Voltage
Circuit Description
The fuel level sensor changes resistance based on the fuel level in the fuel tank. The engine control module (ECM)
monitors changes in the resistance of the sensor to determine the fuel level. This information is then sent to the
instrument cluster via the GM LAN serial data circuit.
W hen the fuel tank is full, the sensor resistance is high and the ECM senses high signal voltage. W hen the fuel tank is
empty, the sensor resistance is low and the ECM senses a low signal voltage.
W hen the ECM senses a signal voltage outside the normal operating range of the sensor, a fuel level sensor DTC will
set.
Conditions for Running the DTC
The ignition is on.
Conditions for Setting the DTC
DTC P0461
The ECM detects that greater than 170 km have been accumulated and the fuel level in the fuel tank has not changed
by at least 3.0 litres.
DTC P0462
The ECM detects the fuel level signal voltage is less than 0.5 V for 20 seconds.
DTC P0463
The ECM detects the fuel level signal voltage is greater than 4.5 V for 20 seconds.
Conditions for Clearing the DTC
The fuel level sensor circuit DTCs are Type C DTCs. Refer to 1.4 Diagnostic Trouble Codes in this Section, for action
taken when Type C DTCs set and conditions for clearing Type C DTCs.
Additional Information
• Refer to 8A Electrical-Body and Chassis for further information on the fuel gauge system.
• Depending on the current fuel level, it may be difficult to locate a malfunctioning sending unit. The malfunction may
only occur when the fuel level is full or near empty. The fuel sender unit may need to be removed for further
diagnosis. A fuel level sensor that has an intermittent condition may cause a DTC to set. Remove the fuel level
sensor to test the resistance of the sensor, refer to 6C Fuel System – V6 for this procedure. Replace the sensor if
the resistance is not within the specified range.
• The following may occur with a fuel level sensor DTC set:
• The vehicle fuel gauge displays empty.
• Since a 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 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.

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Engine Management – V6 – Diagnostics Page 6C1-2–127

DTC P0461, P0462 or P0463 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 or road test the vehicle under various driving condition.
3 Using Tech 2, select the DTC display function.
Does DTC P0461, P0462, P0463 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Switch off the ignition.
2 Disconnect the fuel level sensor wiring connector.
3 Switch on the ignition with the engine not running.
4 Using a digital multimeter, measure the voltage between the fuel level signal circuit and the ECM housing.
Does the multimeter indicate 4.8 – 5.2 V? Go to Step 4 Go to Step 5
4 1 Switch off the ignition.
2 Remove ECM Fuse F29 from the engine compartment fuse and relay panel assembly.
3 Using a digital multimeter, measure the resistance between the fuel level sensor low reference circuit and the ECM housing.
NOTE
Install the ECM Fuse F29 to the engine compartment fuse
and relay panel assembly after completing this test.
Does the multimeter indicate less than 5 Ω? Go to Step 7 Go to Step 6
5 Test the fuel level sensor signal circuit 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.
W as any fault found and rectified? Go to Step 9 Go to Step 8
6 Test the fuel level sensor low reference circuit 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.
W as any fault found and rectified? Go to Step 9 Go to Step 8
7 Replace the fuel level sensor. Refer to 6C Fuel System – V6s
.
W as the repair completed? Go to Step 9 –
8 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as 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.
Do any fuel level sensor DTCs fail this ignition cycle? Go to Step 2 Go to Step 10

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Engine Management – V6 – Diagnostics Page 6C1-2–128

Step Action Yes No
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.
7.26 DTC P0480, P0691 or P0692
DTC Descriptors
This diagnostic procedure supports the following DTCs:
• DTC P0480 – Cooling Fan Relay 1 Circuit Malfunction
• DTC P0691 – Cooling Fan Relay 1 Circuit Low Voltage
• DTC P0692 – Cooling Fan Relay 1 Circuit High Voltage
Circuit Description
The engine control relay applies ignition positive battery voltage to the ignition circuit of the engine cooling fan relay 1
and relay 2. Using a device called a driver, the ECM performs the following tasks:
• grounds the engine cooling fan relay 1 control signal circuit to operate the small engine cooling fan, or
• grounds the engine cooling fan relay 2 control signal circuit to operate both the small engine cooling fan and the
large engine cooling fan.
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.
A cooling fan relay control circuit DTC sets if the ECM detects a fault condition in the engine cooling fan relay control
circuit.
Conditions for Running the DTC
Run continuously once the following conditions are met:
• the ignition voltage is 10 – 16 V,
• the engine speed is greater than 40 rpm, and
• the ECM driver transitions from on to off or from off to on.
Conditions for Setting the DTC
DTC P0480
The ECM detects an open circuit fault condition in the control circuit of the engine cooling fan relay 1.
DTC P0691
The ECM detects a short to ground fault condition in the control circuit of the engine cooling fan relay 1.
DTC P0692
The ECM detects a short to voltage fault condition in the control circuit of the engine cooling fan relay 1.
Conditions for Clearing DTC
The cooling fan relay control circuit DTCs are Type B DTCs. Refer to 1.4 Diagnostic Trouble Codes in this Section, for
action taken when Type B DTCs set and conditions for clearing Type B DTCs.
Additional Information
• Refer to 6B1 – Engine Cooling – V6 for details of the engine cooling fan operation.

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Engine Management – V6 – Diagnostics Page 6C1-2–129

• 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 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
DTC P0480, P0691 & P0692 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 Start the engine.
3 Allow the engine to reach the normal operating temperature.
4 Increase the engine speed to 2,000 rpm for 10 seconds or operate the vehicle within the conditions for setting the DTC.
5 Using Tech 2, select the DTC display function.
Does DTC P0480, P0691 or P0692 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Remove the appropriate engine cooling fan relay. Refer to 8A
Electrical-Body and Chassis.
2 Connect a test lamp between the ignition voltage circuit of the engine cooling fan relay and the ECM housing.
3 Switch on the ignition with the engine not running.
Does the test lamp illuminate? Go to Step 4 Go to Step 5
4 1 Switch off the ignition.
2 Connect a test lamp between the control circuit of the appropriate engine cooling fan relay and a 12 V.
3 Switch on the ignition with the engine not running.
4 Using Tech 2, command the appropriate engine cooling fan relay on and then off.
Does the test lamp turn on and off when the engine cooling fan relay
is commanded on and off? Go to Step 7 Go to Step 6
5 Repair the high resistance or open circuit fault condition in the ignition
voltage circuit of the engine cooling fan relay. Refer to 8A Electrical -
Body and Chassis for information on electrical wiring repair
procedures.
W as the repair completed? Go to Step 9 —
6 Test the engine cooling fan relay control circuit 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.
W as any fault found and rectified? Go to Step 9 Go to Step 8
7 Replace the faulty engine cooling fan relay. Refer to 8A Electrical-
Body and Chassis.
W as the repair completed? Go to Step 9 —

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Engine Management – V6 – Diagnostics Page 6C1-2–130

Step Action Yes No
8 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as 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 cooling fan relay 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.
7.27 DTC P0500
DTC Descriptor
This diagnostic procedure supports DTC P0500 – Vehicle Speed Sensor Circuit Malfunction (Manual Transmission).
Circuit Description
Vehicle speed information is provided to the engine control module (ECM) by the vehicle speed sensor (VSS). The
ignition control relay applies ignition positive voltage to the VSS, and the ground circuit of the VSS is directly connected
to ground.
The VSS is a Hall effect switch. In conjunction with an 18 tooth reluctor wheel, the VSS provide a signal voltage to the
ECM. The ECM uses this signal voltage to determine vehicle speed.
If the ECM detects no vehicle speed, while other sensors indicate that the vehicle is moving, then DTC P0500 sets.
Conditions for Running the DTC
Runs once the following conditions are met:
• The engine coolant temperature is greater than 40º C,
• the ECM is in fuel shut-off mode, and
• the engine speed is between 1,520 and 3,520 rpm
Conditions for Setting the DTC
The ECM detects a speed of less than 0 km/h for 8 seconds continuously, or 50 seconds cumulative.
Conditions for Clearing the DTC
The vehicle speed sensor circuit malfunction DTC is a Type C DTC. Refer to 1.4 Diagnostic Trouble Codes in this
Section, for action taken when Type C DTCs set and conditions for clearing Type C DTCs.
Additional Information
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• Refer to 6C1-1 Engine Management – V6 – General Information for details on:
• VSS operation, and
• fuel shut-off mode.

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Engine Management – V6 – Diagnostics Page 6C1-2–131

• Refer to 7B1 Manual Transmission – V6 for VSS replacement procedures.
• Since a 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 W iring Diagrams and Connector Charts in this Section, for the system wiring
diagram and connector charts.
DTC P0500 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 P0500 fail this ignition cycle? Go to Step 3 Refer to Additional
Information in this DTC
3 1 Switch off the ignition.
2 Disconnect the wiring connector from the VSS.
3 Connect a test lamp between the ignition circuit of the VSS and ground.
4 Switch on the ignition with the engine not running.
Does the test lamp illuminate? Go to Step 5 Go to Step 4
4 Repair the high resistance or open circuit fault condition in the ignition
circuit of the VSS. Refer to 8A Electrical - Body and Chassis for
information on electrical wiring repair procedures.
W as the repair completed? Go to Step 12 —
5 1 Connect a test lamp between the ground circuit and ignition
circuit of the VSS.
2 Switch on the ignition with the engine not running.
Does the test lamp illuminate? Go to Step 7 Go to Step 6
6 Repair the high resistance or open circuit fault condition in the ground
circuit of the VSS. Refer to 8A Electrical - Body and Chassis for
information on electrical wiring repair procedures.
W as the repair completed? Go to Step 12 —

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Engine Management – V6 – Diagnostics Page 6C1-2–132

Step Action Yes No
7

To avoid damage to the drive axles, support the lower
control arms in the normal horizontal position. Do not
run the vehicle in gear with the wheels hanging down
at full travel.
1 Raise the vehicle and support the drive axles with safety stands. Refer to 0A General Information for the location of jacking and
support points.
2 Connect a fused jumper wire between the ground circuit of the connector and the ground circuit of the VSS.
3 Connect a fused jumper wire between the ignition circuit of the connector and the ignition circuit of the VSS.
4 Using connector test adaptor kit J 35616-A, connect a digital multimeter between the VSS signal circuit and ground.
5 Place the transmission in neutral.
6 Rotate the rear wheels by hand while observing the multimeter.
Does the multimeter indicate greater than 0.15 V AC? Go to Step 10 Go to Step 8
8 Perform the following VSS inspection:
• Inspect the VSS wiring harness for conditions that may induce
electromagnetic interference. Refer to 5.2 Intermittent Fault
Conditions in this Section.
• Inspect the VSS for incorrect installation or incorrect attaching
bolt torque value. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
• Inspect the VSS sensor reluctor wheel for damage or conditions
that causes misalignment.
W as any fault found and rectified? Go to Step 12 Go to Step 9
9 Replace the VSS. Refer to 7B1 Manual Transmission – V6.
W as the repair completed? Go to Step 12 —
10 Test the VSS signal circuit 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.
W as any fault found and rectified? Go to Step 12 Go to Step 11
11 Replace the ECM. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
W as the repair completed? Go to Step 12 —
12 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 DTC P0500 fail this ignition cycle? Go to Step 2 Go to Step 13

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