Circuit ISUZU KB P190 2007 Workshop Repair Manual

ENGINE DRIVEABILITY AND EMISSIONS 6E–133
6 Using the DVM and check the IAT sensor.1. Ignition “Off”, engine “Off”.
2. Disconnect IAT sensor connector.
3. Measure the resistance of IAT sensor.
Does the tester indicate standard resistance as shown
in the following table?
Standard
resistance Go to Step 7Go to Step 12
7 Using the DVM and check the IAT sensor signal circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the IAT sensor connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
Approximately 5.0V Go to Step 10Less than 1V:
Go to Step 8
More than
specified value: Go to Step 9
8 Repair the open circuit between the ECM and IAT sensor.
Was the problem solved?
— Verify repair Go to Step 14
9 Repair the short to voltage circuit between the ECM and IAT sensor.
Was the problem solved?
— Verify repair Go to Step 14
Step
Action Value(s) Yes No
Temperature (°C) Resistance (Ω) (Approximately)
-20 32500
09 91 0
20 3400
40 1509
60 670
80 329
100 182
120 101
21
IAT Sensor
Ω
12
V
C121
1
C56(J2) C121
122
C56(J2) C121
122

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ISUZU KB P190 2007

6E–134 ENGINE DRIVEABILITY AND EMISSIONS
10 Using the DVM and check the IAT sensor groundcircuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the IAT sensor connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 11Repair faulty
harness and verify repair
11 Using the DVM and check the IAT sensor ground 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 IAT sensor connector.
4. Check the circuit for open circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the IAT sensor connector.
3. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 14
12 Substitute a known good IAT sensor assembly and recheck.
Was the problem solved? — Go to Step 13Go to Step 14
13 Replace the IAT sensor assembly. Is the action complete? — Verify repair —
14 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 15
Step
Action Value(s) Yes No
V
C121
2
J2-1Breaker BoxC-1212
Ω
C56(J2) C121
21

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6E–136 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0117 ENGINE COOLANT TEMPERATURE SENSOR LOW INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
engine control module (ECM) applies a voltage (about 5
volts) through a pull-up resistor to the ECT signal circuit.
When the engine coolant is cold, the sensor (thermistor)
resistance is high, therefore the ECM will measure a
high signal voltage. As the engine coolant warms, the
sensor resistance becomes lower, and the ECT signal
voltage measured at the ECM drops. Diagnostic Trouble
code P0117 set when the ECM detects an excessively
low signal voltage on the engine coolant temperature
sensor signal circuit.
Diagnostic Aids
Check for the following conditions:
• Poor connection at ECM - 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, short to ground, short to battery positive,
and open circuit. If the harness appears to be OK,
observe the ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the ECT
sensor. A change in the ECT display will indicate the
location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0117 A Engine Coolant Temperature Sensor Low Input 1. Engine run time is longer than 120 sec-
onds.
2. ECT sensor output is more than 149 deg. C. The ECM uses default engine coolant
temperature value based on intake air
temperature and engine run time.

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6E–138 ENGINE DRIVEABILITY AND EMISSIONS
7 Using the DVM and check the ECT sensor signalcircuit.
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 ECT sensor connector.
4. Check the circuit for short to sensor ground or ground circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the ECT sensor connector.
3. Check the circuit for short to sensor ground or ground circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 10
8 Substitute a known good ECT sensor assembly and recheck.
Was the problem solved? — Go to Step 9Go to Step 10
9 Replace the ECT sensor. Is the action complete? — Verify repair —
10 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 11
11 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
J1-27J1-32
Ω
Breaker Box
Ω
E60(J1)
2732

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ENGINE DRIVEABILITY AND EMISSIONS 6E–139
DIAGNOSTIC TROUBLE CODE (DTC) P0118 ENGINE COOLANT TEMPERATURE SENSOR HIGH INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
engine control module (ECM) applies a voltage (about 5
volts) through a pull-up resistor to the ECT signal circuit.
When the engine coolant is cold, the sensor (thermistor)
resistance is high, therefore the ECM will measure a
high signal voltage. As the engine coolant warms, the
sensor resistance becomes less, and the ECT signal
voltage measured at the ECM drops. Diagnostic Trouble
code P0118 set when the ECM detects an excessively
high signal voltage on the engine coolant temperature
sensor signal circuit.
Diagnostic Aids
Check for the following conditions:
• Poor connection at ECM - 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, short to ground, short to battery positive,
and open circuit. If the harness appears to be OK,
observe the ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the ECT
sensor. A change in the ECT display will indicate the
location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0118 A Engine Coolant Temperature Sensor High Input 1. Engine run time is longer than 120 sec-
onds.
2. ECT sensor output is below -38 deg.C. The ECM uses default engine coolant
temperature value based on intake air
temperature and engine run time.

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ENGINE DRIVEABILITY AND EMISSIONS 6E–141
7 Using the DVM and check the ECT sensor signalcircuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the ECT sensor connector.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
Approximately 5.0V Go to Step 10Less than 1V:
G o t o S t e p 8 More than
specified value: Go to Step 9
8 Repair the open circuit between the ECM and ECT sensor.
Was the problem solved?
— Verify repair Go to Step 14
9 Repair the short to voltage circuit between the ECM and ECT sensor.
Was the problem solved?
— Verify repair Go to Step 14
10 Using the DVM and check the ECT sensor ground circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the ECT sensor connector.
3. Check the circuit for short to power supply circuit.
Was the DVM indicated specified value?
Less than 1V Go to Step 11Repair faulty
harness and verify repair
Step
Action Value(s) Yes No
V
E69
1
E60(J1) E69
27
1
E60(J1) E69
27
1
V
E69
2

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6E–142 ENGINE DRIVEABILITY AND EMISSIONS
11 Using the DVM and check the ECT sensor groundcircuit.
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 ECT sensor connector.
4. Check the circuit for open circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the ECT sensor connector.
3. Check the circuit for open circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 14
12 Substitute a known good ECT sensor assembly and recheck.
Was the problem solved? — Go to Step 13Go to Step 14
13 Replace the ECT sensor. Is the action complete? — Verify repair —
14 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 15
15 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
J1-32Breaker Box
Ω
E-692
232E60(J1)E69

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ENGINE DRIVEABILITY AND EMISSIONS 6E–143
DIAGNOSTIC TROUBLE CODE (DTC) P0122 THROTTLE POSITION SENSOR LOW INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The throttle position sensor circuit provides a signal
voltage that changes relative to throttle blade angle. The
signal voltage will vary from below 1 volt at closed
throttle to about 4 volts at wide open throttle (WOT).
The TPS signal is used by the engine control module
(ECM) for fuel control and most of the ECM-controlled
outputs. If the ECM detect a continuous short to ground
in the TPS or circuit, then a code P0122 will set.
Diagnostic Aids
• Poor connection at ECM - 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, short to ground, short to battery positive,
and open circuit. If the harness appears to be OK,
observe the throttle position display on the Tech 2
while moving connectors and wiring harnesses
related to the TPS. A change in the display will
indicate the location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0122 A Throttle Position Sensor Low Input TPS output voltage is below 0.14V. The ECM uses 0% condition as substitute.

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ENGINE DRIVEABILITY AND EMISSIONS 6E–145
7 Using the DVM and check the TPS power supplycircuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the TPS connector.
3. Check the circuit for open or short to ground circuit.
Was the DVM indicated specified value?
Approximately 5.0V Go to Step 9Go to Step 8
8 Repair the open or short to ground circuit between the ECM and TPS.
Was the problem solved?
— Verify repair Go to Step 12
Step
Action Value(s) Yes No
V
E68
2
2E60(J1) E68
15

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6E–146 ENGINE DRIVEABILITY AND EMISSIONS
9 Using the DVM and check the TPS signal 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 TPS connector.
4. Check the circuit for open, short to sensor ground or short to ground circuit.
Was the problem found?
Breaker box is not available: 1. Ignition “Off”, engine “Off”.
2. Disconnect the TPS connector and ECM connector.
3. Check the circuit for open, short to sensor ground or short to ground circuit.
Was the problem found?
—Repair faulty
harness and verify repair Go to Step 12
10 Substitute a known good TPS and recheck. Was the problem solved? — Go to Step 11Go to Step 12
11 Replace the TPS. Is the action complete? — Verify repair-
12 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 12
13 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
J1-7J1-32
Ω
Breaker BoxE-86
Ω
3333
Ω
3273E60(J1) E68

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