2007 ISUZU KB P190 Wiring harness

Engine Management – V6 – Diagnostics Page 6C1-2–177

10 1 Ignition OFF.
2 Disconnect the front and rear HO2S.
3 Inspect the front and rear HO2S for the following conditions:
− Damaged wiring between the HO2S and
the ECM – An intermittent circuit condition
causes this DTC to set.
− Terminal corrosion or water intrusion in the
HO2S harness connectors.
− The correct terminal tension.
− The HO2S is securely installed.
− Any exhaust leaks – Refer to 6F Exhaust
System – V6.
4 Repair as necessary. Refer to 8A Electrical - Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 11
11 1 Disconnect the ECM.
2 Test the appropriate front HO2S circuits for being shorted together between the HO2S connector
and the ECM. Refer to 8A Electrical - Body and
Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 13
12 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 17
13 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 16
14 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 18
15 1 Repair the circuit as necessary. Refer to 8A
Electrical - Body and Chassis.
Did you complete the repair? —
Go to Step 19 —
16 1 Replace the appropriate HO2S. Refer to the
Oxygen Sensor 1 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
17 1 Replace the appropriate HO2S. Refer to the
Oxygen Sensor 2 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
18 1 Replace the ECM. Refer to Engine Control
Module (ECM) Remove, Reinstall and ECM
Reset in 6C1- Engine Management – V6 Service
Operations.
Did you complete the replacement? —
Go to Step 19 —

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–200

10 1 Ignition OFF.
2 Disconnect the front and rear heated oxygen sensors.
3 Inspect the front and rear heated oxygen sensors for the following conditions:
− For damaged wiring between the HO2S
and the ECM – An intermittent circuit
condition may cause this DTC to set.
− For terminal corrosion or water intrusion in
the HO2S harness connectors.
− For the correct terminal tension.
− The HO2S is securely installed and not
damaged.
− For any exhaust leaks – Refer to 6F
Exhaust System – V6.
8 Repair as necessary. Refer to 8A Electrical - Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 11
11 1 Disconnect the ECM.
2 Test the appropriate front heated oxygen sensor circuits for being shorted together between the
HO2S connector and the ECM. Refer to 8A
Electrical - Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 13
12 1 Test for shorted terminals and for poor
connections at the HO2S. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 17
13 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 16
14 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 18
15 1 Repair the circuit as necessary. Refer to 8A
Electrical - Body and Chassis.
Did you complete the repair? —
Go to Step 19 —
16 1 Replace the HO2S 1. Refer to the Oxygen
Sensor 1 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —
17 1 Replace the HO2S 2. Refer to the Oxygen
Sensor 2 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–204

9 1 Shake the related HO2S harnesses for the rear
sensor between the HO2S harness connector
and the ECM while monitoring the appropriate
HO2S voltage parameter.
Does the HO2S parameter change abruptly while
moving the related harnesses? —
Go to Step 15 Go to Step 10
10 1 Ignition OFF.
2 Disconnect the front and rear heated oxygen sensors.
3 Inspect the front and rear heated oxygen sensors for the following conditions:
− For damaged wiring between the HO2S
and the ECM – An intermittent circuit
condition may cause this DTC to set.
− For terminal corrosion or water intrusion in
the HO2S harness connectors.
− For the correct terminal tension.
− The HO2S is securely installed and not
damaged.
− For any exhaust leaks – Refer to 6F
Exhaust System – V6.
8 Repair as necessary. Refer to 8A Electrical - Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 11
11 1 Disconnect the ECM.
2 Test the appropriate front heated oxygen sensor circuits for being shorted together between the
HO2S connector and the ECM. Refer to 8A
Electrical - Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 13
12 1 Test for shorted terminals and for poor
connections at the HO2S. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 17
13 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 16
14 1 Test for shorted terminals and for poor
connections at the ECM. Refer to 8A Electrical -
Body and Chassis.
Did you find and correct the condition? —
Go to Step 19 Go to Step 18
15 1 Repair the circuit as necessary. Refer to 8A
Electrical - Body and Chassis.
Did you complete the repair? —
Go to Step 19 —
16 1 Replace the HO2S 1. Refer to the Oxygen
Sensor 1 procedure, in 6C1- Engine
Management – V6 Service Operations.
Did you complete the replacement? —
Go to Step 19 —

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–213

Conditions for Clearing the DTC
The HO2S pumping current 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 HO2S system operation.
• For an intermittent fault condition, refer to 5.2 Intermittent Fault Conditions in this Section.
• Inspect the HO2S wiring harness for contact with the exhaust system.
• The HO2S must be tightened correctly. A loose HO2S will trigger these DTCs.
• 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 following numbers refer to the step numbers in the diagnostic table:
2 W hen performing this test, the HO2S should react immediately.
4 Connecting a jumper wire between the HO2S reference signal circuit and the low reference circuit causes the ECM to apply signal voltage to the pumping current and input pumping current.
DTC P2237, P2238, P2239, P2240 or P2242 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 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.
5 Using Tech 2, select the DTC display function.
Does DTC P2237, P2238, P2239, P2240, P2241,
P2242, fail this ignition cycle? —
Go to Step 3 Refer to Additional
Information in this DTC

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ISUZU KB P190 2007

Engine Management – V6 – Diagnostics Page 6C1-2–216

• The ignition voltage is between 10.7 – 18.0 volts.
• The fuel system is in fuel shut-off mode.
• The calculated exhaust temperature is less than 750°C.
• The heated oxygen sensors are at operating temperature.
• DTC P2626 and P2629 runs continuously once the above conditions are met.
Conditions for Setting the DTC
• The ECM internal HO2S voltage is more than 4.81 volts.
• The condition exists for more than 4 seconds or 600 seconds if the fuel level is less than 12 percent.
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 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
• 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.
• 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

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ISUZU KB P190 2007

Engine Management – V6 – Service Operations Page 6C1-3–2

Reinstall ................................................................................................................................................................ 20
ECM Reset ...................................................................................................................... ...................................... 20
2.8 Engine Control Module Bracket Assembly......................................................................................... ............... 21
Remove ................................................................................................................................................................. 21
Reinstall ................................................................................................................................................................ 21
2.9 Engine Oil Level and Temperature Sensor ........................................................................................ ................ 22
Remove ................................................................................................................................................................. 22
Test ....................................................................................................................................................................... 23
Engine Oil Level Sensor Check .................................................................................................. ...................... 23
Reinstall ................................................................................................................................................................ 23
2.10 Engine Oil Pressure Sensor..................................................................................................... ........................... 23
Remove ................................................................................................................................................................. 23
Reinstall ................................................................................................................................................................ 24
2.11 Evaporative Emission (EVAP) Canister Purge Valve Quick Connect Fittings ................................................ 24
Disconnect..................................................................................................................... ....................................... 24
Locking Lever Type ............................................................................................................. ............................. 25
Latch Type ....................................................................................................................................................... 25
Connect ............................................................................................................................................................ 25
2.12 Evaporative Emission Canister Purge Valve ...................................................................................... ............... 26
Remove ................................................................................................................................................................. 26
Test ....................................................................................................................................................................... 27
Resistance Check ............................................................................................................... ............................. 27
Functional Test................................................................................................................................................. 27
Reinstall ................................................................................................................................................................ 28
2.13 Fuel Rail Assembly ............................................................................................................. ................................. 28
Remove ................................................................................................................................................................. 28
Disassemble ......................................................................................................................................................... 30
Fuel Injector ..................................................................................................................................................... 30
Fuel Injector Wiring Harness Assembly.......................................................................................... .................. 32
Reinstall ................................................................................................................................................................ 33
2.14 Heated Oxygen Sensor........................................................................................................... ............................. 33
Service Precautions............................................................................................................................................. 33
Six Wire Sensor................................................................................................................................................ 34
Four Wire Sensor ............................................................................................................... .............................. 35
Test ....................................................................................................................................................................... 37
Heater Resistance Check – Six Wire HO2S........................................................................................ ............. 37
Heater Resistance Check – Four Wire HO2S ....................................................................................... ........... 37
2.15 Ignition Coil .......................................................................................................................................................... 38
Ignition Coils ................................................................................................................. ....................................... 38
Remove ............................................................................................................................................................ 38
Disassemble..................................................................................................................................................... 39
Reassemble ..................................................................................................................................................... 39
Test .................................................................................................................................................................. 39
Reinstall ........................................................................................................................................................... 40
2.16 Intake Air Duct Assembly....................................................................................................... ............................. 40
Remove ................................................................................................................................................................. 40
Reinstall ................................................................................................................................................................ 40
2.17 Intake Air Temperature Sensor .................................................................................................. ......................... 41
Test ....................................................................................................................................................................... 41
Resistance Check ............................................................................................................... ............................. 41
2.18 Knock Sensor, Bank 2 (LHS)..................................................................................................... .......................... 42
Remove ................................................................................................................................................................. 42
Reinstall ................................................................................................................................................................ 43
2.19 Knock Sensor, Bank 1 (RHS) ..................................................................................................... ......................... 43
Remove ................................................................................................................................................................. 43
Reinstall ................................................................................................................................................................ 44
2.20 Mass Air Flow Sensor........................................................................................................... ............................... 45
Handling Precautions .......................................................................................................................................... 45
Remove ................................................................................................................................................................. 45
Reinstall ................................................................................................................................................................ 46

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Engine Management – V6 – Service Operations Page 6C1-3–9

2 General Service Operations
2.1 Accelerator Pedal Position Sensor
Remove
1 Turn the ignition switch off.
2 Disconnect the wiring harness connector (1) from the accelerator pedal position (APP) sensor (2) by
depressing the latch in the direction of the arrow.
NOTE
If difficulty is experienced in disconnecting the
harness connector from the APP sensor, remove
the sensor and mounting bracket assembly and
then disconnect the harness connector.
3 Remove the nut (3), two places, attaching the APP sensor and bracket assembly to the dash panel.
Figure 6C1-3 – 2

Reinstall
Reinstallation of the accelerator pedal position (APP) sensor is the reverse of the removal procedure, noting the
following:
1 Reinstall the bolts attaching the APP sensor to the support bracket and tighten to the correct torque specification.
Accelerator pedal position sensor attaching bolt
torque specification ...................................8.5 – 11.5 Nm
2 Road test the vehicle and check for correct operation.
2.2 Air Cleaner Assembly
Air Cleaner Upper Housing
Remove
1 Turn the ignition switch off.
2 Remove the mass air flow (MAF) sensor, refer to 2.20 Mass Air Flow Sensor.

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Engine Management – V6 – Service Operations Page 6C1-3–11

3 Using a suitable lever, gently lever the locking tangs
(1) of the lower housing insulator sleeve back to clear
the lower housing retaining bolt (2). Repeat this
process for each of the remaining two sleeves.
4 Remove the three bolts retaining the lower housing (3) to the fender inner panel and remove the housing.
5 If required, remove the insulator sleeve and air cleaner lower housing insulator (4).
Figure 6C1-3 – 4

Reinstall
1 Reinstall the air cleaner lower housing attaching bolt and tighten to the correct torque specification.
Air cleaner lower housing attaching
bolt torque specification ..........................18.0 – 22.0 Nm
2 Using a suitable hammer and pin punch, position the locking tang against the bolt head.
3 Road test the vehicle and check for correct operation.
2.3 Barometric Pressure Sensor
Remove
1 Turn the ignition switch off.
2 Disconnect the wiring harness connector (1) from the barometric pressure (BARO) sensor (2).

Figure 6C1-3 – 5

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