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 6C1-2–18
4 Diagnostics Starting Point
4.1 Basic Requirements
Basic Knowledge Required
A lack of basic understanding regarding
electronics, electrical wiring circuits and use
of electrical circuit testing tools when
performing an engine management system
diagnostic procedure could result in incorrect
diagnostic results or damage to engine
management system components.
Understanding of the following is required to perform the diagnostic procedures detailed in this Section. Refer to 8A
Electrical - Body and Chassis and to Basic Tools Required.
• Basic electronics,
• Electrical wiring circuits,
• Electrical circuits testing, and
• Correct use of the basic engine management system diagnostic tools.
In addition, understanding of the engine management system is essential to prevent misdiagnosis and component
damage. Refer to 6C1-1 Engine Management – V6 – General Information.
Basic Tools Required
Use of incorrect electrical circuit diagnostic
tools when performing the Engine
Management diagnostic procedures could
result in incorrect diagnostic results or
damage to engine management system
components.
The following electrical circuit testing tools are required to perform the diagnostic procedures detailed in this Section.
• Tech 2,
• Test lamp, refer to 8A Electrical - Body and Chassis, and
• Digital multimeter with 10 M Ω impedance, refer to 8A Electrical - Body and Chassis.
4.2 Diagnostic Precautions
The following precautions must be observed when performing the powertrain diagnostic procedure, otherwise incorrect
diagnostic results or damage to engine management system components will occur:
• Disconnection of the battery affects certain vehicle electronic systems. Refer to 6D1-3 Battery – V6 before
disconnecting the battery.
• Disconnect the battery negative lead when performing the following procedures:
− Disconnecting the ECM connectors, or
− Charging the battery.
• Disconnect the battery terminal lead and the ECM connectors before attempting any electric arc welding on the
vehicle.
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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 6C1-2–20
• Ensure the resistance between the ECM housing and the battery negative cable is less than 0.5 Ω.
• Check the ECM bracket fasteners for correct torque value.
• Check all engine management related components for correct installation.
• Inspect the vacuum hoses for splits, kinks, oil contamination and proper connections, refer to the vehicle emission
control information label. Check the hoses thoroughly for any type of leak or restriction.
• Inspect the air intake ducts for being collapsed, split or for having damaged areas.
• Inspect for air leaks at the throttle body mounting area, mass air flow (MAF) sensor, intake manifold and intake
manifold sealing surfaces.
• Check for wiring harness routing that may be positioned too close to a high voltage or high current device such as
the following:
− Secondary ignition components, and
− Motors and generators.
NOTE
High voltage or high current devices may induce
electrical noise on a circuit, which can interfere
with normal circuit operation.
4.4 Diagnostic System Check
Description
The engine management diagnostic procedure is organised in a logical structure that begins with the Diagnostic System
Check. The Diagnostic System Check directs the diagnostic procedure to the logical steps necessary to diagnose an
engine driveability fault condition.
Test Description
The following numbers refer to the step numbers in the diagnostic table:
6 Tests the integrity of the GM LAN serial data communication circuit. A PIM DTC sets if the PIM detects a fault condition in the communication circuit. A fault condition on the serial data communication circuit may trigger
multiple DTCs on other sensors and components.
Step Action Yes No
1 Have you read the basic requirements?
Go to Step 2 Refer to
4.1 Basic
Requirements
2 Have you read the diagnostic precautions?
Go to Step 3 Refer to
4.2 Diagnostic Precautions
3 Have you performed the preliminary checks?
Go to Step 4 Refer to
4.3 Preliminary Checks
4 Using Tech 2, attempt to communicate with the PIM.
Does the PIM fail to communicate? Refer to 6E1
Powertrain Interface Module – V6 Go to Step 5
5 Does DTC B3902, C0550, U2100, U2105, U2106, P0633, or P1611
also set in the PIM? Refer to 6E1
Powertrain Interface Module – V6 Go to Step 6
6 Using Tech 2, view and record DTCs set at the ECM and TCM.
Does Tech 2 display any DTC? Go to Step 7 Refer to
5.1 Symptoms
Diagnosis Table
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ISUZU KB P190 2007
Engine Management – V6 – Diagnostics Page 6C1-2–41
Figure 6C1-2 – 11
Legend
1 Fuel Injector Tester – Special Tool J39021
2 Digital Multimeter
3 Fuel Injector Harness Adapter – Special Tool J44602 4 To Battery Positive Terminal
5 Battery Earth
Fuel Injector Coil Test Example – Engine Coolant Temperature 10 – 32 °
°°
°
C (Typical Values Shown)
Fuel Injector No. Voltage Reading Pass / Fail (acceptable range 5.5 - 6.6 V)
1 6.6 Pass
2 5.4 Fail
3 6.2 Pass
4 6.1 Pass
5 6.7 Fail
6 6.0 Pass
Figure 6C1-2 – 12
Fuel Injector Coil Test Example – Engine Coolant Temperature Greater / Less Than 10 – 32 °
°°
°
C (Typical Values
Shown)
Fuel Injector No. Voltage Reading Highest Voltage Reading (9.5 V or less) Subtracted Value
(acceptable voltage 0.6 V) Pass / Fail
1 9.8 – – Fail
2 6.4 7.0 0.6 Pass
3 6.9 7.0 0.1 Pass
4 5.8 7.0 1.2 Fail
5 7.0 7.0 0.0 Pass
6 6.3 7.0 0.7 Fail
Figure 6C1-2 – 13
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ISUZU KB P190 2007
Engine Management – V6 – Diagnostics Page 6C1-2–43
6 Remove the upper intake manifold assembly, refer to 6A1 Engine Mechanical – V6.
NOTE
After removing the upper intake manifold, plug
the lower manifold opening to prevent dirt and
other contaminants from entering.
7 Connect Tool No. J 39021 Fuel Injector Tester (1), and Tool No. J 44602 (3) to the fuel injector connector. Refer to Figure 6C1-2 – 14.
Figure 6C1-2 – 14
Legend
1 Fuel Injector Tester – Special Tool J39021
2 Fuel Pressure Gauge – Special Tool SD28018
3 Fuel Injector Harness Adapter – Special Tool J44602
4 To Battery Positive Terminal 5 Battery Earth
6 First Pressure Reading
7 Second Pressure Reading
8 Connect the fuel injector tester battery positive lead (4) and battery negative lead (5) to the battery, refer to Figure 6C1-2 – 14.
9 Set the amperage supply selector of the fuel injector tester to the Balance Test 0.5 – 2.5 A position.
As the fuel pressure tends to increase after
the fuel injector stops fuel delivery, record the
fuel pressure value immediately after the fuel
injector stops fuel delivery. Do not record the
higher fuel pressure value.
10 Press the Push to Start Test Button on the fuel injector tester to activate the fuel injector.
11 Record the fuel pressure reading indicated by the fuel pressure gauge.
NOTE
The fuel pressure readings taken in Step 10 is
known as the second pressure reading
12 Repeat the balance test pressure reading for each fuel injector.
13 Perform the Fuel Injector Pressure Drop Calculation in this Section.
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Engine Management – V6 – Diagnostics Page 6C1-2–47
6.7 Throttle Body Relearn
A throttle body relearn procedure is performed in one of two ways:
• Engine Control Module initiated throttle body relearn, or
• Tech 2 initiated throttle body relearn.
Engine Control Module Throttle Body Relearn
The engine control module (ECM) will automatically perform a throttle body relearn procedure if either of the following
conditions exist:
• The battery has been disconnected, or
• The ignition switch is in the ON position for greater than 29 seconds, and the following conditions are met:
− Engine speed is less than 40 rpm,
− Vehicle speed is 0 km/h,
− Engine coolant temperature is 5 – 60°C,
− Intake air temperature is 5 – 60°C,
− Accelerator pedal position sensor angle is less than 14.9%, and
− Ignition voltage is greater than 10 V.
Tech 2 Throttle Body Relearn
To perform a throttle body relearn using Tech 2, complete the following procedure:
NOTE
Tech 2 will not initiate a throttle body relearn if
the engine is running.
1 Connect Tech 2 to the data link connector (DLC) and turn the ignition on.
2 On Tech 2 select Engine / Programming / Throttle Body Relearn.
3 W hen Tech 2 displays ‘Do you really want to Reset?’, press the ‘Yes’ soft key.
4 W hen Tech 2 displays ‘Programming Completed’, and the electronic throttle control value displayed by Tech 2 is ‘11’, press the ‘Confirm’ soft key to return to the Tech 2 Programming screen.
5 The throttle body relearn is now complete.
6.8 Electronic Ignition (EI) System Diagnosis
Circuit Description
The engine control module (ECM) controls the ignition coils by pulsing the ignition control (IC) circuits, which triggers an
ignition coil and fires the spark plug. The ECM controls the sequencing and the timing of each ignition coil. The ignition
system consist of the following components:
• The six ignition coils
• The crankshaft position (CKP) sensor
• The four camshaft position (CMP) sensors
• The ECM
The ignition coils use the following circuits:
• An IC circuit
• An ignition 1 voltage circuit
• Two ground circuits
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Engine Management – V6 – Diagnostics Page 6C1-2–48
Additional Information
• Use the J 35616-B Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a
component harness connector.
• Inspect the ignition coils for aftermarket devices. An aftermarket device connected to the ignition coil circuits, may
cause a condition with the ignition coils.
• 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.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
4 The ignition coils for each bank are fused separately. If a fuse opens or the ignition 1 voltage circuit opens between the fuse and the splice, all the ignition coils for one bank of the engine would be inoperative. If the ground
circuit opens at the engine block, the ignition coils would be inoperative for one bank of the engine.
5 This step tests for an open or a high resistance in the ignition 1 voltage circuit of the ignition coil. If the DMM does not display near battery voltage there is an open or a high resistance in the circuit.
6 This step determines if the ground circuit is open. If the circuit is open, the ignition coils would be inoperative for one bank of the engine.
7 This step determines if the ignition 1 voltage circuit is shorted to ground. If the fuse is open, the ignition coils would be inoperative for one bank of the engine.
Diagnostic Table
Step Action Value(s) Yes No
1
Has the Diagnostic System Check been performed? —
Go to Step 2 Refer to
4.4 Diagnostic System Check
2 W ere you sent here from DTC P0300 or P0301-P0306? —
Go to Step 3 Go to DTC P0300 or
DTC P0301 – P0306
3 1 Start the engine.
2 Allow the engine to reach operating temperature.
3 Operate the engine at 2,000 rpm.
4 Monitor all of the Misfire Current Counters with a scan tool. There are a total of 6 counters,
1 counter per cylinder.
Are any of the Misfire Current Counters incrementing? —
Go to Step 4 Go to
5.2 Intermittent Fault Conditions
4 Are all the misfire counters incrementing for one bank
of the engine? —
Go to Step 7 Go to Step 5
5 1 Ignition OFF.
2 Disconnect the appropriate ignition coil.
3 Ignition ON, engine OFF.
4 Connect a test lamp between the battery voltage circuit of the ignition coil and a good ground.
5 Measure the voltage between the probe of the test lamp and a good ground with a DMM. Refer
to 8A Electrical - Body and Chassis for the
procedure to measure voltage drop.
Is the voltage at the specified value? B+
Go to Step 6 Go to Step 9
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