service ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–285
DIAGNOSTIC TROUBLE CODE (DTC) P1105 (SYMPTOM CODE 1)
(FLASH CODE 86) BAROMETRIC PRESSURE SENSOR CIRCUIT HIGH INPUT
DIAGNOSTIC TROUBLE CODE (DTC) P1105 (SYMPTOM CODE 2)
(FLASH CODE 86) BAROMETRIC PRESSURE SENSOR CIRCUIT LOW INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The ECM monitors the barometric pressure signal at
inside of the ECM. If the sensor with malfunction, DTC
P1105 (Symptom Code 1) or P1105 (Symptom Code 2)
will be stored.
Diagnostic Aids
If the DTC P1105 is stored, sensor or circuit of ECM
inside is failed.
Diagnostic Trouble Code (DTC) P1105 (Sy mptom Code 1) (Flash Code 86)
Barometric Pressure Sensor Circuit High Input
Diagnostic Trouble Code (DTC) P1105 (Sy mptom Code 2) (Flash Code 86)
Barometric Pressure Sensor Circuit Low Input
Flash
CodeCode Symptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
86 P1105 1 ON Ba rome tric Pressure Se nsor
Circuit High InputBa rome tric pressure senso r
output voltage is more than
4.4V.ECM use s 1013hpa condition
as substitute .
2 ON Ba rome tric Pressure Se nsor
Circuit Lo w InputBa rome tric pressure senso r
output voltage is below 1.5V.
Step Action Value(s) Yes No
1Was 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 As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1105 (Symptom Code 1) or P1105
(Symptom Code 2) stored as “Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1105 (Symptom Code 1) or P1105
(Symptom Code 2) stored in this ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 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 5

6E–286 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
5 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

6E–292 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
11 Using the DVM and check the TPS ground circuit.
Breaker box is available:
1. Ignition “Off”, engine “Off”.
2. Install the breaker box as type A. (ECM
disconnected) Ref. Page 6E-103
3. Disconnect the TPS 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 TPS connector and ECM
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 TPS and recheck.
Was the problem solved?—Go to Step 13Go to Step 14
13 Replace the TPS.
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
E-2249Breaker Box




49
1C-56
E-22

6E–294 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
6 Using the DVM and check the TPS power supply
circuit.
1. Ignition “On”, engine “Off”.
2. Disconnect the TPS connector.
3. Check the circuit for short to ground circuit.
Was the DVM indicated specified value?
Approx imately
5.0V Go to Step 12Go to Step 7
7 Repair the short to battery voltage circuit between the
ECM and TPS.
Was the problem solved?
—Verify repair Go to Step 8
8 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 9Go to Step 10
9 Replace the TPS.
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
V3 E-22
57
3 C-56
E-22

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–297
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 13
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

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–299
13 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 14
14 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

6E–300 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P1120 (Symptom Code E) (Flash Code 21)
Pedal/Throttle Position Sensor Idle Position Switch Error
Step Action Value(s) Yes No
1Was 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 As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P1120 (Symptom Code E) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1120 (Symptom Code E) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Visually check the TPS.
Was the problem found? —Go to Step 8Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
Does the Tech 2 indicate correct “Throttle Position”
from 0% to 100% depending on accelerator pedal
operation?—Go to Step 7Go to Step 6Go
to Step 6
6 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Throttle Position” in the data display.
3. Adjust the TPS within 0% to 100%.
Was the problem solved?—Verify repair Go to Step 8
7 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Monitor the “Idle Switch” in the data display.
Does the Tech 2 indicate “Inactive” when the
accelerator pedal was stepped on?—Go to Step 10Go to Step 8
8 Substitute a known good TPS and recheck.
Was the problem solved?—Go to Step 9Go to Step 10
9 Replace the TPS.
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

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–301
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

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–303
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P1173 (Symptom Code 3) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
and Go to Step
4
4 Check the engine overheat condition.
Was the problem found?
—Repair the
cause of
overheat and
verify repair Go to Step 5
5 1. Using the Tech 2, ignition “On” and engine “On”.
2. Monitor the “Coolant Temperature” in the data
display.
Does the Tech 2 indicate correct “Coolant
Temperature” depending on warm up time?—Go to Step 9Go to Step 6
6 Using the DVM and check the ECT sensor.
1. Ignition “Off”, engine “Off”.
2. Disconnect ECT sensor connector.
3. Measure the resistance of ECT sensor.
Does the tester indicate standard resistance as shown
in the following table?
Standard
resistance Go to Step 9Go to Step 7
7 Substitute a known good ECT sensor assembly and
recheck.
Was the problem solved?—Go to Step 8Go to Step 9
8 Replace the ECT sensor.
Is the action complete?—Verify repair—
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 Step Action Value(s) Yes No
Temperature (°C) Re sista nce (
) (Appro xima te ly )
-20 16100
0 5760
20 2370
40 1080
60 537
80 290
100 161
120 95
1 2
ECT Sensor
1 2

6E–304 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
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