2007 ISUZU KB P190 relay

Engine Management – V6 – Diagnostics Page 6C1-2–15

C-56–28 Not Used
C-56–29 V HI_SIG_3 B1S2 O2 Sensor High Signal (Bank 1 Sensor 2)
C-56–30 Not Used
C-56–31 R/W CRANK_REQ Crank Voltage
C-56–32 B PRKNEU Park/Neutral Switch Signal
C-56–33 Not Used
C-56–34 Not Used
C-56–35 Y START_RLY Starter Relay Coil Control
C-56–36 BR/R BATT + Battery Positive Voltage
C-56–37 Not Used
C-56–38 PU SDI Data Link Connector (DLC) Serial Data
C-56–39 R 5VDC1 5 Volt Reference 1
C-56–40 BR 5VGD5 Low Reference – Ground 5
C-56–41 P RTN_4 B2S2 O2 Sensor Low Signal (Bank 2 Sensor 2)
C-56–42 Y/R FUEL_LVL1 Fuel Level Sensor Signal
C-56–43 Y MAF MAF Sensor Signal
C-56–44 Y PED_POS_2 APP Sensor 2 Signal
C-56–45 Not Used
C-56–46 GR/R CRU_ETC_TCC Brake Switch (S220 – ‘C’) Cruise Cancel Signal
C-56–47 Not Used
C-56–48 Not Used
C-56–49 GR/R AC_CLU A/C Compressor Clutch Relay Control
C-56–50 BR/Y MIL Malfunction indicator Lamp
C-56–51 Not Used
C-56–52 Not Used
C-56–53 BR CRCTL_CLU_SW Clutch Switch (S42) Cruise Cancel Signal
C-56–54 Not Used
C-56–55 R/G CAN_LO_2 GMLAN Serial Data Bus – Low
C-56–56 BR/Y 5VDC3 5 Volt Reference 3
C-56–57 BR/R RTN_3 B1S2 O2 Sensor Low Signal (Bank 1 Sensor 2)
C-56–58 R/Y ACC Accessory Voltage
C-56–59 Not Used
C-56–60 L PED_POS_1 APP Sensor 1 Signal
C-56–61 V HI_SIG_4 B2S2 O2 Sensor High Signal (Bank 2 Sensor 2)
C-56–62 Not Used
C-56–63 Not Used
C-56–64 Not Used

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–19

• Do not start the engine if the battery terminal is not properly secured to the battery.
• Do not disconnect or reconnect the following while the ignition is switched on or when the engine is running:
− Any engine management system component electrical wiring connector, or
− Battery terminal leads.
• Ensure the correct procedure for disconnecting and connecting engine management system electrical wiring
connectors is always followed. For information on the correct procedure for disconnecting and connecting specific
wiring connectors, refer to 6C1-3 Engine Management – V6 – Service Operations.
• Ensure that all wiring harness connectors are fitted correctly.
• W hen steam or pressure cleaning engines, do not direct the cleaning nozzle at engine management system
components.
• Do not clear any DTCs unless instructed.
• The fault must be present when using the diagnostic trouble code (DTC) diagnostic tables. Otherwise,
misdiagnosis or replacement of good parts may occur.
• Do not touch the ECM connector pins or soldered components on the ECM circuit board to prevent ECM
Electrostatic Discharge damage. Refer to 8A Electrical - Body and Chassis for information on Electrostatic
Discharge.
• Use only the test equipment specified in the diagnostic tables as other test equipment may give incorrect results or
damage good components.
• The ECM is designed to withstand normal current draw associated with vehicle operations. However, the following
fault conditions or incorrect test procedure may overload the ECM internal circuit and damage the ECM:
− A short to voltage fault condition in any of the ECM low reference circuits may cause internal ECM and / or
sensor damage. Therefore, any short to voltage fault condition in the ECM low reference circuits must be
rectified before replacing a faulty component.
− A short to ground fault condition in any of the ECM 5 V reference circuits may cause internal ECM and / or
sensor damage. Therefore, any short to ground fault condition in the ECM 5 V reference circuits must be
rectified before replacing a faulty component.
− W hen using a test lamp to test an electrical circuit, do not use any of the ECM low reference circuits or 5 V
reference circuits as a reference point. Otherwise, excessive current draw from the test lamp may damage
the ECM.
• Disregard DTCs that set while performing the following diagnostic Steps:
− Using Tech 2 actuator tests, or
− Disconnecting an engine management system sensor connector then switching on the ignition.
• After completing the required diagnostics and service operations, road test the vehicle to ensure correct engine
management system operation.
4.3 Preliminary Checks
The preliminary checks are a set of visual and physical checks or inspections that may quickly identify engine
management system fault condition.
• Refer to the appropriate Service Techlines for relevant information regarding the fault condition.
• Ensure the battery is fully charged.
• Inspect the battery connections for corrosion or a loose terminal.
• Ensure that all engine management system related fuses are serviceable.
• Inspect for incorrect aftermarket theft deterrent devices, lights or mobile phone installation.
• Ensure there is no speaker magnet positioned too close to any electronic module that contains relays.
• Inspect the engine wiring harness for proper connections, pinches or cuts.
• Ensure that all engine management related electrical wiring connectors are fitted correctly.
• Inspect the ECM ground connections for corrosion, loose terminal or incorrect position.

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–23

• there is no Current DTC but a History DTC is stored.
Diagnostic Table
Checks Actions
Preliminary
• Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Gather information from the customer regarding the conditions that trigger the
intermittent fault such as:
• At what engine or ambient temperature range does the fault occur?
• Does the fault occur when operating aftermarket electrical equipment inside
the vehicle?
• Does the fault occur on rough roads or in wet road conditions?
• If the intermittent fault is a start and then stall condition, check the immobiliser
system. Refer to 11A Immobiliser.
Tech 2 Tests The following are lists of Tech 2 diagnostic tests that may be used to diagnose
intermittent faults:
• W riggle test the suspected wiring harness and connectors while observing Tech 2
operating parameters. If Tech 2 read-out fluctuates during this procedure, check
the tested wiring harness circuit for a loose connection.
• Observe the freeze frame / failure records for the suspected history DTC and then
operate the vehicle in the conditions that triggers the intermittent fault while an
assistant observes the suspected Tech 2 operating parameter data.
• Capture and store data in the snapshot mode when the fault occurs. The stored
data may be played back at a slower rate to aid diagnostics. Refer to Tech 2 User
Instructions for further information on the Snapshot function.
• Compare the engine operating parameters of the engine being diagnosed to the
engine operating parameters of a known good engine.
Malfunction Indicator Lamp The following conditions may cause an intermittent Malfunction Indicator Lamp fault with no DTC listed:
• Electromagnetic interference (EMI) caused by a faulty relay, ECM controlled
solenoid, switch or other external source.
• Incorrect installation of aftermarket electrical equipment such as the following:
• mobile phones,
• lights, or
• radio equipment.
• ECM grounds are loose.

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Engine Management – V6 – Diagnostics Page 6C1-2–24

Checks Actions
Temperature Related Temperature related intermittent fault condition occurs only when the engine or ambient
temperature is hot, or only when it is cold.
• If the intermittent fault is heat related, review Tech 2 data in relationship to the
following:
• high ambient temperature,
• engine generated heat,
• circuit generated heat due to a poor electrical connection or high electrical
load, and
• higher than normal load conditions (towing, etc.).
• If the intermittent fault is related to cold ambient or engine temperature, review
Tech 2 data in relationship to the following:
• low ambient temperature, and
• the fault condition that occurs only on a cold start situation.
Additional Tests
• Incorrect installation of aftermarket electrical equipment such as the following:
• mobile phones,
• theft deterrent alarms,
• lights, or
• radio equipment.
• Electromagnetic interference (EMI) caused by a faulty relay, ECM controlled
solenoid or switch. The fault is triggered when the relay or solenoid is activated.
• Test the A/C compressor clutch and some relays that contain a clamping diode or
resistor for an open circuit.
• Test the generator for a faulty rectifier bridge that may allow the A/C noise into the
ECM electrical circuit.
When all diagnosis and repairs are completed, check the system for correct operation.
5.3 Backfire
Description
The air / fuel mixture in the intake manifold or in the exhaust system ignites which produces a loud popping noise.
Checks Actions
Preliminary Perform the Preliminary Checks. Refer to 4.3 Preliminary Checks in this
Section.
Sensor / System • Check the air intake system and crankcase for air leaks.
• Check the PCV System for correct operation. Refer to 6A1 Engine Mechanical –
V6.
• Use Tech 2 to monitor the knock sensor system for excessive spark retard
activity. Check for items that cause spark retard activity.

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Engine Management – V6 – Diagnostics Page 6C1-2–26

5.4 Cranks But Does Not Run
Definition
The engine cranks normally but does not start.
Checks Actions
Preliminary • Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Check the immobiliser system for correct operation. Refer to 11A Immobiliser.
Sensor / System
• Check the engine coolant temperature (ECT) sensor for an incorrect value.
Compare the engine coolant temperature against the intake air temperature (IAT)
on a cold engine. The ECT and IAT sensor values should be within ± 3°C of each
other. Refer to 6C1-3 Engine Management – V6 – Service Operations for details
of the Temperature vs. Resistance Table.
• Check the mass air flow (MAF) sensor installation. Incorrect installation of the
MAF sensor may cause hard start condition. Refer to 6C1-3 Engine Management
– V6 – Service Operations.
• Check for a dirty starter motor commutator or brushes that can mask the
crankshaft position sensor signal.
Fuel System • Check the fuel system for the following fault conditions. Refer to 6C Fuel System
– V6.
• restricted fuel filter,
• incorrect fuel pressure,
• contaminated fuel, and
• incorrect fuel pump relay operation.
• Check the operation of the fuel injectors. Refer to 6C1-3 Engine Management –
V6 – Service Operations.
Ignition System • Inspect for moisture or corrosion around the spark plug / ignition coil area.
• Test the ignition coil voltage output. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
• Remove and inspect the spark plugs. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
NOTE
If the spark plugs are fouled, determine the cause of the fouling before
replacing the spark plugs. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
Check for loose ignition coil ground circuit.
Engine Mechanical • Check for excessive oil in combustion chamber. Refer to 6A1 Engine Mechanical
– V6.
• Check for the following engine fault conditions. Refer to 6A1 Engine Mechanical –
V6.
• low compression, and
• worn valve train components.
When all diagnosis and repairs are completed, check the system for correct operation.

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–29

Checks Actions
Preliminary Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this Section.
Fuel System Inspect the injectors for leaking condition. Refer to 6C1-3 Engine Management – V6 –
Service Operations.
Engine Cooling System • Check for engine overheating. Refer to 6B1 Engine Cooling – V6.
• Check the engine thermostat for proper operation and correct heat range. Refer to
6B1 Engine Cooling – V6.
Engine Mechanical • Check for build up of carbon deposit in the combustion chamber, which may
cause hot spots and increased compression ratio. Refer to 6A1 Engine
Mechanical – V6.
• Using Tech 2, check for incorrect engine idle speed.
Additional
• If the engine continues to run after the ignition is switched off but the engine runs
normally, check the following:
• ignition switch operation,
• voltage feedback from alternator L terminal to ignition switch, and
• sticking ignition control relay.
When all diagnosis and repairs are completed, check the system for correct operation.
5.8 Hard Start
Definition
The engine cranks normally but takes longer to start than usual. As soon as the engine runs, the engine may stall
immediately.
Checks Actions
Preliminary • Perform the preliminary checks. Refer to 4.3 Preliminary Checks in this
Section.
• Check the immobiliser system for correct operation. Refer to 11A Immobiliser.
Sensor / System
• Check the engine coolant temperature (ECT) sensor for an incorrect value.
Compare the engine coolant temperature against the intake air temperature (IAT)
on a cold engine. The ECT and IAT sensor values should be within ± 3°C of each
other. Refer to 6C1-3 Engine Management – V6 – Service Operations for details
of the Temperature vs. Resistance Table.
• Check the mass air flow (MAF) sensor installation. Incorrect installation of the
MAF sensor may cause hard start condition. Refer to 6C1-3 Engine Management
– V6 – Service Operations.
• Test the resistance of the crankshaft position (CKP) sensor. The CKP sensor
resistance must be within 700 – 1,200 Ω at all temperatures.
• Check for dirty starter motor commutator or brushes that can mask the crankshaft
position sensor signal.
Fuel System • Check the fuel system for the following fault conditions. Refer to 6C Fuel System
– V6.
• restricted fuel filter,
• incorrect fuel pressure, and
• contaminated fuel.
• Check the operation of the fuel injectors. Refer to 6C1-3 Engine Management –
V6 – Service Operations.

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–55

DTC Description Diagnostic Table
P0341 Intake Camshaft Position Sensor Range / Performance
(Bank 1) 7.21 DTC P0341, P0342 or P0343
P0342 Intake Camshaft Position Sensor Low Voltage (Bank 1) 7.21 DTC P0341, P0342 or P0343
P0343 Intake Camshaft Position Sensor High Voltage (Bank 1) 7.21 DTC P0341, P0342 or P0343
P0351 Ignition Coil Cylinder 1 Circuit Malfunction
7.22 DTC P0351, P0352, P0353, P0354,
P0355, P0356, P2300, P2301, P2303,
P2304, P2306, P2307, P2309, P2310,
P2312, P2313, P2315 or P2316
P0352 Ignition Coil Cylinder 2 Circuit Malfunction 7.22 DTC P0351, P0352, P0353, P0354,
P0355, P0356, P2300, P2301, P2303,
P2304, P2306, P2307, P2309, P2310,
P2312, P2313, P2315 or P2316
P0353 Ignition Coil Cylinder 3 Circuit Malfunction 7.22 DTC P0351, P0352, P0353, P0354,
P0355, P0356, P2300, P2301, P2303,
P2304, P2306, P2307, P2309, P2310,
P2312, P2313, P2315 or P2316
P0354 Ignition Coil Cylinder 4 Circuit Malfunction 7.22 DTC P0351, P0352, P0353, P0354,
P0355, P0356, P2300, P2301, P2303,
P2304, P2306, P2307, P2309, P2310,
P2312, P2313, P2315 or P2316
P0355 Ignition Coil Cylinder 5 Circuit Malfunction 7.22 DTC P0351, P0352, P0353, P0354,
P0355, P0356, P2300, P2301, P2303,
P2304, P2306, P2307, P2309, P2310,
P2312, P2313, P2315 or P2316
P0356 Ignition Coil Cylinder 6 Circuit Malfunction 7.22 DTC P0351, P0352, P0353, P0354,
P0355, P0356, P2300, P2301, P2303,
P2304, P2306, P2307, P2309, P2310,
P2312, P2313, P2315 or P2316
P0420 Catalytic System – Low Efficiency (Bank 1) 7.23 DTC P0420 or P0430
P0430 Catalytic System – Low Efficiency (Bank 2) 7.23 DTC P0420 or P0430
P0443 Evaporative Emission Control System Purge Solenoid
Circuit Malfunction 7.24 DTC P0443, P0458 or P0459
P0458 Evaporative Emission Control System Purge Solenoid
Circuit Low Voltage 7.24 DTC P0443, P0458 or P0459
P0459 Evaporative Emission Control System Purge Solenoid
Circuit High Voltage 7.24 DTC P0443, P0458 or P0459
P0460 Fuel Level Sensor Range / Performance
7.25 DTC P0460, P0461, P0462 or P0463
P0461 Fuel Level Sensor Range / Performance 7.25 DTC P0460, P0461, P0462 or P0463
P0462 Fuel Level Sensor Low Voltage 7.25 DTC P0460, P0461, P0462 or P0463
P0463 Fuel Level Sensor High Voltage 7.25 DTC P0460, P0461, P0462 or P0463
P0480 Cooling Fan Relay 1 Circuit Malfunction 7.26 DTC P0480, P0691 or P0692
P0500 Vehicle Speed Sensor Circuit Malfunction 7.27 DTC P0500
P0504 Brake Switch Circuit Malfunction 7.28 DTC P0504 or P0571
P0506 Idle Speed Control rpm Too Low 7.29 DTC P0506, P0507, P0638, P1551,
P2100, P2101, P2119 or P2176
P0507 Idle Speed Control rpm Too High 7.29 DTC P0506, P0507, P0638, P1551,
P2100, P2101, P2119 or P2176
P0513 W rong Transponder Key 7.30 DTC P0513, P0633, P1629, P1632,
P1677, P1678 or P1679
P0521 Oil Pressure Sensor Range / Performance 7.31 DTC P0521, P0522 or P0523

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Engine Management – V6 – Diagnostics Page 6C1-2–56

DTC Description Diagnostic Table
P0522 Oil Pressure Sensor Voltage Low 7.31 DTC P0521, P0522 or P0523
P0523 Oil Pressure Sensor Voltage High 7.31 DTC P0521, P0522 or P0523
P0532 A/C Pressure Sensor Voltage Low 7.32 DTC P0532 or P0533
P0533 A/C Pressure Sensor Voltage High 7.32 DTC P0532 or P0533
P0560 System Voltage Malfunction 7.33 DTC P0560, P0562 or P0563
P0562 System Voltage Low Voltage 7.33 DTC P0560, P0562 or P0563
P0563 System Voltage High Voltage 7.33 DTC P0560, P0562 or P0563
P0571 Cruise Control Brake Switch Circuit 7.28 DTC P0504 or P0571
P0601 Replace Electronic Control Unit (ECU) 7.34 DTC P0601, P0602, P0604 or P0606
P0602 Program Electronic Control Unit (ECU) 7.34 DTC P0601, P0602, P0604 or P0606
P0604 Replace Electronic Control Unit (ECU) 7.34 DTC P0601, P0602, P0604 or P0606
P0606 Replace Electronic Control Unit (ECU) 7.34 DTC P0601, P0602, P0604 or P0606
P0615 Starter Relay Circuit Malfunction 7.35 DTC P0615, P0616 or P0617
P0616 Starter Relay Circuit Low Voltage 7.35 DTC P0615, P0616 or P0617
P0617 Starter Relay Circuit High Voltage 7.35 DTC P0615, P0616 or P0617
P0625 Alternator F Terminal Low Voltage 7.36 DTC P0625 or P0626
P0626 Alternator F Terminal High Voltage 7.36 DTC P0625 or P0626
P0627 Fuel Pump Relay Circuit Malfunction 7.37 DTC P0627, P0628 or P0629
P0628 Fuel Pump Relay Voltage Low 7.37 DTC P0627, P0628 or P0629
P0629 Fuel Pump Relay Voltage High 7.37 DTC P0627, P0628 or P0629
P0633 Immobiliser Function Not Programmed 7.30 DTC P0513, P0633, P1629, P1632,
P1677, P1678 or P1679
P0638 Commanded Versus Actual Throttle Position Correlation 7.29 DTC P0506, P0507, P0638, P1551, P2100, P2101, P2119 or P2176
P0645 A/C Relay Circuit Malfunction 7.38 DTC P0645, P0646 or P0647
P0646 A/C Relay Voltage Low 7.38 DTC P0645, P0646 or P0647
P0647 A/C Relay Voltage High 7.38 DTC P0645, P0646 or P0647
P0685 Engine Control Ignition Relay Circuit Malfunction 7.39 DTC P0685, P0686 or P0687
P0686 Engine Control Ignition Relay Circuit Low Voltage 7.39 DTC P0685, P0686 or P0687
P0687 Engine Control Ignition Relay Circuit High Voltage 7.39 DTC P0685, P0686 or P0687
P0691 Cooling Fan Relay 1 Circuit Low Voltage 7.26 DTC P0480, P0691 or P0692
P0692 Cooling Fan Relay 1 Circuit High Voltage 7.26 DTC P0480, P0691 or P0692
P0700 Malfunction Indicator (MI) Request from Transmission
Control Module (TCM) 7.40 DTC P0700
P0704 Clutch Switch Input Circuit Malfunction
7.41 DTC P0704
P0850 Park / Neutral Signal Circuit Incorrect Signal 7.42 DTC P0850
P1258 Engine Coolant Over Temperature – Protection Mode
Active 7.8 DTC P0116, P0117, P0118, P0125 or
P1258
P1551 Throttle Control Lower Position Not Reached during Learning Mode 7.29 DTC P0506, P0507, P0638, P1551,
P2100, P2101, P2119 or P2176

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