2007 ISUZU KB P190 Circuit

ENGINE DRIVEABILITY AND EMISSIONS 6E–209
Diagnostic Trouble Code (DTC) P0650
Malfunction Indicator Lamp (MIL) Control Circuit Malfunction
Step Action Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check” performed?
—Go to Step 2Go to
On Board
Diagnostic
(OBD) System Check
2 1. Connect the Tech 2. 2. Review and record the failure information.
3. Select “F0: Read DTC Infor By Priority” in “F0: Diagnostic Trouble Code”.
Is the DTC P0650 stored as “Present Failure”? — Go to Step 3Refer to
Diagnostic Aids and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”. 2. Select “Clear DTC Information” with the Tech2 andclear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed This Ignition” in “F2: DTC Information”.
Was the DTC P0650 stored in this ignition cycle? — Go to Step 4Refer to
Diagnostic Aids and Go to Step
4
4 1. Ignition “On”, engine “Off”. 2. Check the “Check Engine” lamp.
Does the lamp turn “On”? — Go to Step 5Go to Step 6
5 1. Ignition “On”, engine “Off”. 2. Check the “Check Engine” lamp.
Does the lamp turn “Off”? — Go to Step 9Go to Step 7
6 Check the “Check Engine” lamp bulb. If the bulb is burnt out, repair as necessary.
Was the problem found? — Verify repair Go to Step 7
7 Check for poor/faulty connection at the meter connector and ECM connector. If a poor/faulty
connection is found, repair as necessary.
Was the problem found?
— Verify repair Go to Step 8
32
17
C-56(J2)B-24

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ISUZU KB P190 2007

6E–210 ENGINE DRIVEABILITY AND EMISSIONS
8 Using the DVM and check the “Check Engine” lampcircuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM disconnected) Refer to 6E-88 page.
3. Remove the meter connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Remove the meter connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 9
9 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 10
10 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify repair —
Step
Action Value(s) Yes No
J2-25
Breaker BoxB-2411
ΩΩ
C-56(J2)
B-24
3217

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–211
DIAGNOSTIC TROUBLE CODE (DTC) P1167 FUEL SUPPLY SYSTEM RICH DURING DECELERATION FUEL CUT OFF
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) internal circuitry can
identify if the vehicle fuel system is capable of supplying
adequate amounts of fuel during deceleration (fuel cut
off). The ECM monitors the voltage of the oxygen
sensor during fuel cut off. When a fuel cut off mode of
operation is requested during “Closed Loop” operation
(by deceleration), the ECM will provide more fuel to the
engine. Under these conditions the ECM should detect
a “lean” condition (low oxygen sensor voltage). If this “lean” exhaust is not detected at this time, a Diagnostic
Trouble Code P1167 will set.
Diagnostic Aids
Check the following items:
• Fuel pressure - The system will go rich if pressure is too high. The ECM can compensate for some
increase. However, if fuel pressure is too high, a
Diagnostic Trouble Code P1167 may be set. Refer to
Fuel System Diagnosis .
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1167 D Fuel Supply System Rich During Deceleration Fuel Cutoff 1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. O
2 sensor bank 1 output voltage is more
than 550mV in deceleration fuel cutoff
mode. No fail-safe function.

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6E–214 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1171 FUEL SUPPLY SYSTEM LEAN DURING POWER ENRICHMENT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) internal circuitry can
identify if the vehicle fuel system is capable of supplying
adequate amounts of fuel during heavy acceleration
(power enrichment). The ECM monitors the voltage of
the oxygen sensor during power enrichment. When a
power enrichment mode of operation is requested
during “Closed Loop” operation (by heavy acceleration), the ECM will provide more fuel to the engine. Under
these conditions the ECM should detect a “rich”
condition (high oxygen sensor voltage). If this “rich”
exhaust is not detected at this time, a Diagnostic
Trouble Code P1171 will set. A plugged fuel filter or
restricted fuel line can prevent adequate amounts of fuel
from being supplied during power enrichment mode.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1171 D Fuel Supply System Lean During Power Enrichment 1. No DTC relating to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injector control circuit and ignition
control circuit.
2. Engine coolant temperature is more than 60 deg. C.
3. Mass air flow is below 13.5m/s.
4. O
2 sensor bank 1 output voltage is below
350mV in power enrichment mode. No fail-safe function.

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–217
DIAGNOSTIC TROUBLE CODE (DTC) P1625 ECM SYSTEM RESET
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) monitors unexpected
ECM reset. This will not turn on MIL light on, only
records code DTC P1625.
Diagnostic Aids
Check for the follwing conditions:
• P1625 alone stored does not need diagnosis. Clear DTC code.
NOTE: DTC P1625 is a DTC to record a ECM reset
history. If DTC P1625 is not reset and no engine
abnormality occurs after learing the DTC, no farther
diagnostic procedures are required.
Diagnostic Trouble Code (DTC) P1625 ECM System Reset
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1625 B ECM System Reset ECM reset has occurred other than “On”. Engine control disabled.
StepAction Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check” performed?
—Go to Step 2Go to
On Board
Diagnostic
(OBD) System Check
2 1. Connect the Tech 2. 2. Review and record the failure information.
3. Select “F0: Read DTC Infor By Priority” in “F0: Diagnostic Trouble Code”.
Is the DTC P1625 stored as “Present Failure”? — Go to Step 3Refer to
Diagnostic Aids and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”. 2. Select “Clear DTC Information” with the Tech2 andclear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed This Ignition” in “F2: DTC Information”.
Was the DTC P1625 stored in this ignition cycle? — Go to Step 4Refer to
Diagnostic Aids and Go to Step
4
4 Is the Immobilizer function programmed in the ECM? — Verify repair Go to Step 5
5 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 6
6 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify repair —

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ISUZU KB P190 2007

6E–218 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1626 IMMOBILIZER NO SIGNAL
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM decides whether that is an abnomality in the
immobilizer control system. DTC P1626 is recorded by
the ECM when no response from immobiliser.
Diagnostic Aids
Check for the following conditions:
• Poor connection at ECM and Immobilizer-Inspect harness connectors for backed out terminals,
improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire
connection.
• Damaged harness Inspect the wiring harness for damage, If the harness appears to be OK, disconnect
the ECM and Immobilizer, turn the ignition “ON” and
observe a voltmeter connected to the suspect driver
circuit at the ECM and Immobilizer harnass connector
while moving connectors and wiring harnesses
relates to the MIL. A change in voltage will indicate
the location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1626 - Immobilizer No Signal No response from immobilizer control unit. 1. Engine does not start.
2. Check engine lamp flash.

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ENGINE DRIVEABILITY AND EMISSIONS 6E–219
Diagnostic Trouble Code (DTC) P1626 Immobilizer No Signal
StepAction Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check” performed?
—Go to Step 2Go to
On Board
Diagnostic
(OBD) System Check
2 1. Connect the Tech 2. 2. Review and record the failure information.
3. Select “F0: Read DTC Infor By Priority” in “F0: Diagnostic Trouble Code”.
Is the DTC P1626 stored as “Present Failure”? — Go to Step 3Refer to
Diagnostic Aids and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”. 2. Select “Clear DTC Information” with the Tech2 andclear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed This Ignition” in “F2: DTC Information”.
Was the DTC P1626 stored in this ignition cycle? — Go to Step 4Refer to
Diagnostic Aids and Go to Step
4
4 1. Using the Tech 2, ignition “On” and engine “Off”. 2. Select “Immobilizer” in the system selection menu“Body”.
3. Select “Read DTC Info Ordered By Priority” in the “Diagnositic Trouble Code”.
Was the DTC B0007 stored in this ignition cycle? —Refer to
“Immobilizer Workshop
Manual” & Go to DTC Chart B0007 Go to Step 5
5 Check for poor/faulty connection at the immobilizer control unit connector or ECM connector. If a poor/
faulty connection is found, repair as necessary.
Was the problem found?
— Verify repair Go to Step 6
6 Using the DVM and check the “CHECK ENGINE” lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the meter connector and immobilizer control unit connector.
3. Ignition “On”.
4. Check the circuit for short to power supply circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 7
3223 78
C-56(J2) B-68
VV
B-24
B-68
17
7

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ISUZU KB P190 2007

6E–220 ENGINE DRIVEABILITY AND EMISSIONS
7 Using the DVM and check the “CHECK ENGINE”lamp circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM disconnected) Refer to 6E-88 page.
3. Disconnect the immobilizer control unit connector.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the the immobilizer control unit connector and ECM connector.
3. Check the circuit for open or short to ground circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 8
8 Using the DVM and check the VSS signal circuit. 1. Ignition “Off”, engine “Off”.
2. Disconnect the immobilizer control unit connector and ECM connector.
3. Ignition “On”.
4. Check the circuit for short to power supply circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 9
Step
Action Value(s) Yes No
J2-32
Breaker BoxB-24
17
ΩΩ
C-56(J2)
327B-68
VV
C-56(J2)
23
7
B-68

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ISUZU KB P190 2007