2007 ISUZU KB P190 CIRCUIT DIAGRAM

Engine Management – V6 – Diagnostics Page 6C1-2–117

Step Action Yes No
4 1 Switch off the ignition.
2 Remove ECM Fuse 29 from the engine compartment fuse and relay panel assembly.
3 Using a digital multimeter, measure the resistance between the CMP sensor low reference circuit and the ECM housing.
NOTE
Install the ECM Fuse 29 to the engine compartment fuse
and relay panel assembly after completing this test.
Does the multimeter display 5 Ω?
Go to Step 5 Go to Step 8
5 Test the signal circuit of the CMP sensor 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 11 Go to Step 6
6 Perform the following CMP sensor inspection:
• Inspect the sensor wiring harness for conditions that may induce
electromagnetic interference. Refer to
5.2 Intermittent Fault Conditions in this Section.
• Inspect the sensor for incorrect sensor installation or incorrect
attaching bolt torque value. Refer to 6C1-3 Engine Management
– V6 – Service Operations.
• Inspect the CMP sensor reluctor wheel for damage or conditions
that causes misalignment.
W as any fault found and rectified? Go to Step 11 Go to Step 9
7 Test the CMP sensor 5 V reference circuit for a high resistance, open
circuit, short to voltage or short to ground fault condition. Refer to 8A
Electrical - Body and Chassis for information on electrical fault
diagnosis.
NOTE
Each CMP sensor shares a common 5 V reference circuit.
A fault condition in the 5 V reference circuit may trigger
DTCs on all CMP sensors. Refer to 3 W iring Diagrams
and Connector Charts in this Section, to assist diagnosis.
W as any fault found and rectified? Go to Step 11 Go to Step 10
8 Test the CMP sensor low reference circuit for a high resistance or an
open circuit fault condition. Refer to 8A Electrical - Body and Chassis
for information on electrical fault diagnosis.
NOTE
The CMP sensor shares the low reference circuit with
other sensors. A fault condition in the low reference circuit
may trigger DTCs on sensors that share this circuit. Refer
to 3 W iring Diagrams and Connector Charts in this
Section, to aid diagnosis.
W as any fault found and rectified? Go to Step 11 Go to Step 10
9 Replace the appropriate CMP sensor. Refer to 6C1-3 Engine
Management – V6 – Service Operations.
W as the repair completed? Go to Step 11 —

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Engine Management – V6 – Diagnostics Page 6C1-2–119

The ECM applies control voltage to the control circuit of the ignition coil during the calculated dwell period that allows
current flow to the ignition coil primary winding to generate a magnetic flux field. At the appropriate firing point, the ECM
interrupts the control voltage applied to the ignition coil.
Interruption of voltage applied to the control circuit of the ignition coil primary winding induces the transfer of electrical
energy from the ignition coil primary winding to the ignition coil secondary winding, which triggers the ignition coil to
produce a spark at the spark plug.
An ignition coil control circuit DTC sets if the ECM detects a fault condition in the control circuit of an ignition coil.
Conditions for Running the DTC
Run continuously once the following conditions are met:
• The engine is running.
• The engine speed is 480 – 5,000 rpm
• The battery voltage is 10.0 – 16.0 V.
Conditions for Setting the DTC
DTC P0351, P0352, P0353, P0354, P0355 or P0356
The ECM detects an open circuit fault condition in the ignition coil control circuit.
DTC P2300, P2303, P2306, P2309, P2312 or P2315
The ECM detects a short to ground fault condition in the ignition coil control circuit.
DTC P2301, P2304, P2307, P2310, P2313 and P2316
The ECM detects a short to voltage fault condition in the ignition coil control circuit.
Conditions for Clearing the DTC
The ignition coil control circuit DTCs are Type B DTCs. Refer to 1.4 Diagnostic Trouble Codes in this Section, for
action taken when 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 ignition coil operation.
• A short to voltage fault condition damages the ignition coil. Do not replace the ignition until this fault condition is
rectified.
• The ignition coils for each bank of the engine are fused separately. If all DTCs for a single bank are set, there may
be a fault in one of the ignition supply circuits.
• The ignition coils for each bank of the engine have a separate ground connections. If all DTCs for a single bank
are set, there may be a fault in one of the ground circuits.
• 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 numbers refer to the step numbers in the diagnostic table:
3 Determines if there is a fault condition in the ignition voltage supply circuit.
5 Determines if there is a fault condition in the ground circuits of the ignition coil.
6 Tests if the ECM is commanding the ignition coil on and off.

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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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ISUZU KB P190 2007

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 6C1-2–129

• 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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ISUZU KB P190 2007

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 6C1-2–133

Step Action Yes No
13 Using Tech 2, select the DTC display function.
Are there any DTCs displayed? Go to the
appropriate DTC
Table in this Section System OK
When all diagnosis and repairs are completed, check the system for correct operation.
7.28 DTC P0504 or P0571
DTC Descriptor
This diagnostic procedure supports:
• DTC P0504 – Brake Switch Circuit Malfunction.
• DTC P0571 – Cruise Control Brake Switch Circuit
Circuit Description
The brake switch assembly is comprised of two individual switches, a stop lamp switch and cruise control cancel switch.
The ECM uses inputs from both of these switches for enabling cruise control, brake torque management etc. For further
information on the brake switch assemblies, refer to 6C1–1 Engine Management – V6 – General Information.
The ECM monitors both switches, and if the signals do not correlate, DTC P0504 will set. If the ECM determines that a
fault exists in the cruise control cancel circuit, DTC0571 will set.
Conditions for Running the DTC
Run continuously once the following conditions are met:
• The ignition is switched on.
• The ignition voltage is 10.0 – 16.0 V.
Conditions for Setting the DTC
The ECM detects one of the following conditions:
• Only one switch signal is present when the vehicle accelerates or decelerates rapidly ten times.
NOTE
The ECM will count over several drive cycles.
• A signal is seen from the stop lamp switch and cruise control cancel switch when the vehicle accelerates rapidly.
• The ECM does not detect a signal from the switches during braking.
Conditions for Clearing the DTC
The brake switch circuit DTC is a Type B DTC. Refer to 1.4 Diagnostic Trouble Codes in this Section, for action
taken when Type B 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 of the brake switch operation.
• Refer to 8C Cruise Control – HFV6 for brake pedal switch operation and testing.
• 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.

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Engine Management – V6 – Diagnostics Page 6C1-2–137

Conditions for Setting the DTC
DTC P0506
The actual engine speed is less than the desired idle speed by at least 100 rpm for 10 seconds.
DTC P0507
The actual engine speed is greater than the desired idle speed by at least 200 rpm for 10 seconds or the ECM detects
three fuel cut-offs due to an engine over speed condition while the engine is idling.
DTC P0638
The ECM detects the commanded duty cycle is greater than 80 percent for longer than 0.6 second.
DTC P1551
The ECM detects the TP sensor angle is outside the predetermined range of 1.8 – 13.0 percent when the TAC motor is
deactivated.
DTC 2100
The ECM detects that its internal TAC motor output driver does not deactivate when commanded off.
DTC P2101
The ECM detects the difference between the commanded and the actual throttle opening is greater than 10 percent.
DTC P2119
The ECM determines the throttle plate didn't return to the rest position within 720 milliseconds.
DTC P2176
One of the following conditions exist:
• The TP sensor 1 voltage is outside the range of 0.2 – 0.9 V during the throttle learn procedure.
• The TP sensor 2 voltage is outside the range of 4.2 – 4.8 V during the throttle learn procedure.
• The throttle learn procedure is not learned after an ECM replacement.
Conditions for Clearing DTC
The TAC motor control circuit DTCs are Type A DTCs. Refer to 1.4 Diagnostic Trouble Codes in this Section, for
action taken when a Type A DTC sets and conditions for clearing Type A DTCs.
Additional Information
• Refer to 6C1-1 Engine Management – V6 – General Information for details of the Throttle Actuator Control System
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 numbers refer to the step numbers in the diagnostic table:
4 A constant force return spring holds the throttle plate at a constant seven percent throttle opening position and should move in either direction under spring pressure and without binding.
8 W hen the ignition is switched on, the ECM operates the throttle actuator motor to verify the integrity of the TAC system prior to start up. This can be seen by the momentary flash of the test lamp as the ignition is switched on.

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