2007 ISUZU KB P190 ECU

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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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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Engine Management – V6 – Diagnostics Page 6C1-2–57

DTC Description Diagnostic Table
P1629 Immobiliser Fuel Enable Signal Not Received 7.30 DTC P0513, P0633, P1629, P1632,
P1677, P1678 or P1679
P1632 Immobiliser Fuel Disable Signal Received 7.30 DTC P0513, P0633, P1629, P1632,
P1677, P1678 or P1679
P1648 W rong Security Code Entered 7.43 DTC P1648
P1668 Alternator L Terminal Circuit Malfunction 7.44 DTC P1668, P2500 or P2501
P1677 Immobiliser Function not Enabled 7.30 DTC P0513, P0633, P1629, P1632,
P1677, P1678 or P1679
P1678 Engine Control Module Identification Failed 7.30 DTC P0513, P0633, P1629, P1632,
P1677, P1678 or P1679
P1679 Immobiliser Environment Identification Failed 7.30 DTC P0513, P0633, P1629, P1632,
P1677, P1678 or P1679
P1845 Engine Torque Reduction Malfunction 7.45 DTC P1845
P2096 Post Catalyst O2 Sensor Fuel Trim Below Lower Limit
(Bank 1) 7.46 DTC P2096 or P2098
P2097 Post Catalyst O2 Sensor Fuel Trim Above Upper Limit
(Bank 1) 7.47 DTC P2097 or P2099
P2098 Post Catalyst O2 Sensor Fuel Trim Below Lower Limit
(Bank 2) 7.46 DTC P2096 or P2098
P2099 Post Catalyst O2 Sensor Fuel Trim Above Upper Limit
(Bank 2) 7.47 DTC P2097 or P2099
P2100 Throttle Control Motor Malfunction
7.29 DTC P0506, P0507, P0638, P1551,
P2100, P2101, P2119 or P2176
P2101 Throttle Control Position Range / Performance 7.29 DTC P0506, P0507, P0638, P1551,
P2100, P2101, P2119 or P2176
P2105 Throttle Control Forced Engine Shutdown 7.48 DTC P2105
P2107 Throttle Control Malfunction 7.49 DTC P2107
P2119 Closed Throttle Position Range / Performance 7.29 DTC P0506, P0507, P0638, P1551,
P2100, P2101, P2119 or P2176
P2122 Accelerator Pedal Position Sensor 1 Voltage Low 7.50 DTC P2122, P2123, P2127, P2128 or P2138
P2123 Accelerator Pedal Position Sensor 1 Voltage High 7.50 DTC P2122, P2123, P2127, P2128 or P2138
P2127 Accelerator Pedal Position Sensor 2 Voltage Low 7.50 DTC P2122, P2123, P2127, P2128 or P2138
P2128 Accelerator Pedal Position Sensor 2 Voltage High 7.50 DTC P2122, P2123, P2127, P2128 or P2138
P2138 Accelerator Pedal Position Sensor 1-2 Correlation 7.50 DTC P2122, P2123, P2127, P2128 or P2138
P2176 Throttle Control Lower Position not Learned 7.29 DTC P0506, P0507, P0638, P1551,
P2100, P2101, P2119 or P2176
P2177 Fuel Trim Lean during Cruising/Acceleration (Bank 1) 7.51 DTC P2177 or P2179
P2178 Fuel Trim Rich during Cruising/Acceleration (Bank 1) 7.52 DTC P2178 or P2180
P2179 Fuel Trim Lean during Cruising/Acceleration (Bank 2) 7.51 DTC P2177 or P2179
P2180 Fuel Trim Rich during Cruising/Acceleration (Bank 2 7.52 DTC P2178 or P2180
P2187 Fuel Trim Lean during Idling/Deceleration (Bank 1) 7.53 DTC P2187 or P2189
P2188 Fuel Trim Rich during Idling/Deceleration (Bank 1) 7.54 DTC P2188 or P2190

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Engine Management – V6 – Diagnostics Page 6C1-2–88

• DTC P0153 – HO2S Circuit Slow Response – Bank 2 Sensor 1
Circuit Description
The wide band heated oxygen sensor (HO2S) measures the amount of oxygen in the exhaust system and provides
more information than the switching style HO2S. The wide band sensor consists of an oxygen sensing cell, an oxygen
pumping cell, and a heater.
The exhaust gas sample passes through a diffusion gap between the sensing cell and the pumping cell. The engine
control module (ECM) supplies a voltage to the HO2S and uses this voltage as a reference to the amount of oxygen in
the exhaust system. An electronic circuit within the ECM controls the pump current through the oxygen pumping cell to
maintain a constant voltage in the oxygen sensing cell. The ECM monitors the voltage variation in the sensing cell and
attempts to keep the voltage constant by increasing or decreasing the amount of current flow, or oxygen ion flow, to the
pumping cell.
By measuring the amount of current required to maintain the voltage in the sensing cell, the ECM can determine the
concentration of oxygen in the exhaust. The HO2S voltage is displayed as a lambda value. A lambda value of 1 is equal
to a stoichiometric air fuel ratio of 14.7:1. Under normal operating conditions, the lambda value will remain around 1.
W hen the fuel system is lean, the oxygen level will be high and the lambda signal will be high or more than 1. W hen the
fuel system is rich, the oxygen level will be low, and the lambda signal will be low or less than 1. The ECM uses this
information to maintain the correct air / fuel ratio.
Conditions for Running the DTC
• Before the ECM can report DTC P0133 or P0153 failed, DTCs P0121, P0122, P0123, P0221, P0222, P0223,
P0336, P0338, P2237, and P2240 must run and pass.
• DTCs P0030, P0031, P0032, P0050, P0051, P0052, P0053, P0059, P0130, P0131, P0132, P0135, P0150, P0151,
P0151, P0152, P0155, P0442, P0443, P0446, P0455, P0458, P0459, P0496, P167A, P167B, P2096, P2097,
P2098, P2099, P2231, P2234, P2243, P2247, P2251, P2254, P2297, P2298, P2626, and P2629 are not set.
• The HO2S is at operating temperature.
• The HO2S is between 0.94 – 1.06 lambda.
• The engine speed is between 1,480 – 2,040 rpm.
• The volumetric efficiency is between 16.5 – 38.3 percent.
• The change in volumetric efficiency is less than 3 percent.
• The evaporative emission (EVAP) purge is not active, or the ECM determines the EVAP hydrocarbon (HC)
concentration is less than a predetermined amount when EVAP purge is active.
• The long term fuel trim correction is active.
• DTCs P0133 and P0153 run continuously once the above conditions are met for 10 minutes.
Conditions for Setting the DTC
• The ECM has determined that the dynamic value of the affected HO2S is less than a predetermined threshold.
• The above condition is met for more than 4 seconds.
Action Taken When the DTC Sets
• The ECM illuminates 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 MIL/DTC
• The ECM turns OFF the malfunction indicator lamp (MIL) after four consecutive ignition cycles that the diagnostic
runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.

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Engine Management – V6 – Diagnostics Page 6C1-2–89

• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission
related diagnostic.
• Use Tech 2 to clear the MIL/DTC.
Additional Information
• Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a
component harness connector.
• The lower connector of the ECM is connector A43-X1 and the upper connector of the ECM is connector A43-X2.
Refer to 3 W iring Diagrams and Connector Charts in this Section.
• The front wide band sensors do not toggle or switch like a switching HO2S. The front HO2S signals will be
relatively stable for an idling engine.
• 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.
• The following table illustrates the typical voltages for the HO2S circuits:
HO2S Voltages
Conditions: • Ignition ON, Engine OFF
• HO2S Disconnected
HO2S Circuit Voltage
Heater Control 4.6 – 5.0 V
Heater Supply Voltage B+
Reference Voltage 2.6 – 3.1 V
Low Reference 2.2 – 2.7 V
Pump Current Less than 0.5 A
Input Pump Current Less than 0.5 A
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2 This step determines if the condition exists.
4 This step determines if the fuel system is contaminated.
DTC P0133 or P0153 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

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Engine Management – V6 – Diagnostics Page 6C1-2–90

Step Action Yes No
2 NOTE
• DTC P0133 is for bank 1 sensor 1 and DTC P0153 is
for bank 2 sensor 1.
• DTC P0132 causes DTC P0153 to set. If DTC P0132
is set with DTC P0153, refer to 7.10 DTC
P0130, P0131, P0132, P0135, P0137, P0138, P0140,
P0141, P0150 P0151, P0152, P0155, P0157, P0158,
P0160, P0161, P2243, P2247, P2270, P2271, P2272,
P2273, P2297 or P2298 in this Section.
• Inspect the heated oxygen sensor (HO2S) for being
secure before proceeding with this DTC. A sensor that
is loose could cause this DTC to set.
1 Start engine and allow to reach operating temperature.
2 Observe the diagnostic trouble code (DTC) information with Tech 2.
Did DTC P0133 and / or DTC P0153 fail this ignition cycle? Go to Step 4 Go to Step 3
3 1 Observe the Freeze Frame / Failure Records for this DTC.
2 Turn OFF the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you
observed from the Freeze Frame / Failure Records.
Did the DTC fail this ignition? Go to Step 4 Go to Additional
Information in this DTC
4 Did DTC P0133 and DTC P0153 fail this ignition cycle? Go to Step 7 Go to Step 5
5 1 Inspect for an exhaust leak near the HO2S. Refer to 6F Exhaust
System – V6. After you inspect the exhaust system, return to
this diagnostic.
Did you find and correct the condition? Go to Step 8 Go to Step 6
6 1 Inspect or test for the following conditions:
• Inspect that the HO2S is securely installed.
• Inspect for corrosion on the HO2S terminals.
• Inspect the terminal tension at the HO2S and at the
engine control module (ECM). Refer to 8A Electrical-Body
and Chassis.
• Inspect the HO2S wiring for damage.
Did you find and correct the condition? Go to Step 8 Go to Step 7

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Engine Management – V6 – Diagnostics Page 6C1-2–92

P0340, P0341, P0345, P0346, P0351-P0358, P0365, P0366, P0390, P0391, P0442, P0443, P0446, P0449,
P0453, P0454, P0455, P0458, P0459, and P0496 are not set.
• The ECT Sensor parameter is more than 66° C.
• The Vehicle Speed Sensor parameter is between 5 – 180 km/h.
• The calculated catalytic converter temperature is more than 520° C.
• DTC P0139 or P0159 runs continuously once the above conditions are met.
Conditions for Setting the DTC
• The ECM detects that the decel fuel cut-off and rich-to-lean transition time has exceeded 1 second.
Action Taken When the DTC Sets
• The ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the
diagnostic runs and fails.
• The ECM 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 ECM writes the operating conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
• The ECM turns OFF the malfunction indicator lamp (MIL) after three consecutive ignition cycles that the diagnostic
runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission
related diagnostic.
• Use Tech 2 to clear the MIL and the DTC.
DTC P0139 or P0159 Diagnostic Table
Step Action Value(s) Yes No
1
Has the Diagnostic System Check been completed? —
Go to Step 2 Refer to
4.4 Diagnostic System Check
2 1 Start and run the engine until normal operating
temperature is reached.
2 Quickly cycle the throttle from closed throttle to wide open throttle (W OT) 3 times within
5 seconds while observing the HO2S Bank 1
Sensor 2 or HO2S Bank 2 Sensor 2 voltage
parameter with Tech 2.
Does the voltage react immediately when performing
the above action? —
Go to Step 3 Go to Step 4
3 1 Observe the Freeze Frame / Failure Records for
this DTC.
2 Turn OFF the ignition for 30 seconds.
3 Start the engine.
4 Operate the vehicle within the Conditions for Running the DTC. You may also operate the
vehicle within the conditions that you observed
from the Freeze Frame / Failure Records.
Did the DTC fail this ignition? —
Go to Step 4 Go to 5.2
Intermittent Fault Conditions in this Section.

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Engine Management – V6 – Diagnostics Page 6C1-2–102

3-way catalytic converter damage. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for
catalytic converter damage are present. DTCs P0301 through P0306 correspond to cylinders 1 through 6. If the ECM is
able to determine that a specific cylinder is misfiring, the DTC for that cylinder will set. If the misfire rate is sufficient to
cause emission levels to exceed a predetermined value, this DTC sets.
Conditions for Running the DTC
• DTCs P0121, P0122, P0123, P0221, P0222, P0223, P0335, P0336, or P0338 are not set.
• The engine speed is between 400 – 7,000 rpm and steady.
• The delivered torque signal is more than 10 percent at idle.
• The delivered torque signal is between 9 – 30 percent with the transmission in drive.
• The intake air temperature (IAT) is more than –30° C.
• The fuel level is more than 12 percent.
• The torque management is not active.
• DTC P0300 runs continuously when the above conditions exist for at least 1,000 engine revolutions.
Conditions for Setting the DTC
• The ECM detects a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emissions levels
to exceed mandated standards.
• The condition above exists for more than 4 seconds.
Action Taken When the DTC Sets
• The control module activates the MIL on the second 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 MIL/DTC
• The ECM turns OFF the malfunction indicator lamp (MIL) after four consecutive ignition cycles that the diagnostic
runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission
related diagnostic.
• Use Tech 2 to clear the MIL and the DTC.
Additional Information
• A misfire DTC could be caused by an excessive vibration from sources other than the engine. Inspect for the
following possible sources:
− A tyre or wheel that is out of round or out of balance
− Variable thickness brake rotors
− An unbalanced drive shaft
− Certain rough road conditions
− A damaged accessory drive component or belt
• A misfire DTC could be caused by a camshaft actuator stuck in the full advance or retard position.
• For an intermittent condition, refer to 5.2 Intermittent Fault Conditions in this Section.

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