check engine ISUZU TF SERIES 2004 Workshop Manual

6E–112 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
CHECK ENGINE LAMP (MIL) “ON” STEADY
Circuit description
The check engine lamp should always be illuminated
and steady for about five seconds with ignition “ON” and
the engine stopped. Ignition feed voltage is supplied
directly to the check engine lamp indicator. The Engine
Control Module (ECM) turns the check engine lamp
“ON” by grounding the check engine lamp driver circuit.
The check engine lamp should not remain “ON” with the
engine running and no DTC(s) set. A steady check
engine lamp with the engine running and no DTC(s)
suggests a short to ground in the check engine lamp
driver circuit.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:
Poor connection or damaged harness – Inspect the
ECM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal-to-wire connection, and
damaged harness.

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–11 3
Check Engine Lamp (MIL) On Steady
Step Action Value(s) Yes No
1 1. Ignition “Off”, engine “Off”.
2. Disconnect the ECM connector.
3. Ignition “On”.
Was the “CHECK ENGINE” lamp turned on?—Go to Step 2 Go to Step 4
2 Using the DVM and check the “CHECK ENGINE”
lamp circuit.
1. Ignition “Off”, engine “Off”.
2. Disconnect the meter connector and ECM
connector.
3. Check the circuit for short to ground circuit.
Was the problem found?
—Veri fy repai rGo to Step 3
3 Replace the meter assembly.
Is the action complete?—Veri fy repai r—
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?—Veri fy repai rGo to Step 5
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.—Veri fy repai r—
42
17
B-24 C-56

6E–126 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
55 P1605 E ON EEPROM Defect EEPROM checksum does
not match with the read
check sum during
initialization of the ECM.EEPROM checksum match
with the read check sum
during initialization of the
ECM.ECM malfunction.
——
56 P1610 A - Security Key and Security
Code not ProgrammedImmobilizer functions are not
programmed in the ECM.1 . E n g i n e d o e s n o t s t a r t .
2. Check engine lamp flash. No recovery. ECM malfunction.
— B****
56 P1611 A - Wrong Security Code
EnteredReceived security code is not
correct.1 . E n g i n e d o e s n o t s t a r t .
2. Check engine lamp flash. N o r e c o v e r y . 1 . E C M m a l f u n c t i o n .
2. Immobilizer control unit
m a l f u n c t i o n .
3. Transponder key
malfunction.— B****
56 P1612 A - Immobilizer No or Wrong
SignalReceived challenge signal is
not correct or not received.1 . E n g i n e d o e s n o t s t a r t .
2. Check engine lamp flash. No recovery. 1. ECM and immobilizer
control unit
communication circuit
open circuit, short to
ground circuit or short to
voltage circuit.
2 . E C M m a l f u n c t i o n .
3. Immobilizer control unit
m a l f u n c t i o n .
4. Transponder key
malfunction.2 7 /
35B****
56 P1613 A - Immobilizer No or Wrong
SignalReceived response signal is
not correct or not received.1 . E n g i n e d o e s n o t s t a r t .
2. Check engine lamp flash. No recovery. 1. ECM and immobilizer
control unit
communication circuit
open circuit, short to
ground circuit or short to
voltage circuit.
2 . E C M m a l f u n c t i o n .
3. Immobilizer control unit
m a l f u n c t i o n .
4. Transponder key
malfunction.2 7 /
35B****
56 P1614 A - Wrong Transponder Key Received response signal is
not correct from the
transponder key.1 . E n g i n e d o e s n o t s t a r t .
2. Check engine lamp flash. N o r e c o v e r y . 1 . E C M m a l f u n c t i o n .
2. Immobilizer control unit
m a l f u n c t i o n .
3. Transponder key
malfunction.— B****
76 P1625 A OFF ECM Main Relay Switched
Off Too EarlyWhen ignition switch was
turned off, timing of the ECM
main relay turning off is too
early.No fail-safe function. No recovery. ECM malfunction.
3 /
58—
B OFF ECM Main Relay Switched
Off Too LateWhen ignition switch was
turned off, timing of the ECM
main relay turning off is too
late or does not off.No recovery. 1. ECM main relay
m a l f u n c t i o n .
2. ECM malfunction.3 /
58— Flash
CodeCodeSymptom
CodeMILDTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure PartsRelated
ECM Pin
No.Related
Multiple
DTC4JA1-TC
(MT)4JH1-TC
(MT)4JH1-TC
(AT)

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–127
51 P1630 A ON Fuel Injection Quantity
Circuit MalfunctionThe PSG (pump control unit)
detects high pressure
solenoid valve control circuit
malfunction due to high
current.Fuel injection quantity is
reduced.The PSG (pump control unit)
detects correct high pressure
solenoid valve control circuit.PSG (pump control unit)
malfunction.
——
B ON Fuel Injection Quantity
Circuit MalfunctionThe PSG (pump control unit)
detects high pressure
solenoid valve control circuit
malfunction due to
continuous current.1. MAB (fuel cutoff solenoid
v a l v e ) i s o p e r a t e d .
2. Desired injection quantity
becomes 0mg/strk.No recovery. PSG (pump control unit)
malfunction.
——
44 P1650 A ON CAN Device Offline CAN controller detects Bus-
off or canceling.MAB (fuel cutoff solenoid
v a l v e ) i s o p e r a t e d . CAN controller detects
correct Bus signal.1. CAN high circuit open,
short to ground or short
t o v o l t a g e c i r c u i t .
2. CAN low circuit open,
short to ground or short
t o v o l t a g e c i r c u i t .
3. Poor connector
c o n n e c t i o n .
4. Electrical interference.
5. ECM malfunction.
6. PSG (pump control unit)
malfunction.9 9 /
100P1651(B)
B ON CAN Device Hang-up CAN controller does not
react under engine running.CAN controller reacts
correctly under engine
running.1 . E C M m a l f u n c t i o n .
2. PSG (pump control unit)
malfunction.——
45 P1651 A ON CAN Malfunction The PSG (pump control unit)
does not recognize CAN
signal from the CAN
controller.1. MAB (fuel cutoff solenoid
v a l v e ) i s o p e r a t e d .
2. Desired injection quantity
becomes 0mg/strk.The PSG (pump control unit)
recognizes CAN signal from
the CAN controller.1 . E C M m a l f u n c t i o n .
2. PSG (pump control unit)
malfunction.——
B ON CAN Malfunction The ECM does not read CAN
signal from the PSG (pump
control unit).The ECM reads CAN signal
from the PSG (pump control
unit).1. CAN high circuit open,
short to ground or short
to voltage circuit.
2. CAN low circuit open,
short to ground or short
to voltage circuit.
3. Poor connector
connection.
4. Electrical interference.
5. ECM malfunction.
6. PSG (pump control unit)
malfunction.9 9 /
100P1650(A)
77 P1690 4 OFF Check Engine Lamp (MIL)
Circuit Voltage LowCheck engine lamp circuit
open or short to ground
circuit.No fail-safe function. Check engine lamp circuit is
correct condition.1. Check engine lamp
circuit open or short to
g r o u n d c i r c u i t .
2. Check engine lamp
malfunction
3. ECM malfunction.42 B****
8 OFF Check Engine Lamp (MIL)
Circuit Voltage HighCheck engine lamp circuit
short to voltage circuit.ECM malfunction.
—— Flash
CodeCodeSymptom
CodeMILDTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure PartsRelated
ECM Pin
No.Related
Multiple
DTC4JA1-TC
(MT)4JH1-TC
(MT)4JH1-TC
(AT)

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–129
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The mass air flow (MAF) sensor is part of the intake air
system. It is fitted between the air cleaner and
turbocharger and measure the mass air flowing into the
engine.
The mass air flow (MAF) sensor element measures the
partial air mass through a measurement duct on the
sensor housing.
The ECM monitors the MAF sensor supply voltage and
MAF sensor output voltage. The supply voltage is out of
range, DTC P0100 (Symptom Code 7) or P0100
(Symptom Code 9) will be stored. The output voltage
ex cessively high or low, DTC P0100 (Symptom Code B)
or P0100 (Symptom Code C) will be stored.
Diagnostic Aids
An intermittent may be caused by the following:
 Poor connections.
 Misrouted harness.
 Rubbed through wire insulation.
 Broken wire inside the insulation.
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. If the harness appears to be OK, observe
the “Mass Air Flow” display on the Tech2 while
moving connectors and wiring harness related to the
sensor.
Diagnostic Trouble Code (DTC) P0100 (Symptom Code 7) (Flash Code 65)
Mass Air Flow (MAF) Sensor Voltage Supply Circuit High Input
Flash
CodeCodeSymptom
CodeMIL DTC Name DTC Setting Condition Fail-Safe (Back Up)
65 P0100 7 ON Ma ss Air Flo w (MAF) Senso r
Voltage Supply Circuit High
InputMAF sensor power supply
voltage is more than 5.2V.ECM uses ma ss a ir flo w
1600mg/strk & EGR 10% co n-
ditions as substitute.
9 ON Mass Air Flow (MAF) Sensor
Voltage Supply Circuit Low
InputMAF sensor power supply
voltage is below 4.6V.
B ON Mass Air Flow (MAF) Sensor
Output Circuit Low Input1. Engine speed is between
600rpm and 5000rpm.
2. MAF se nsor o utput is
below -33.7mg/strk.
C ON Mass Air Flow (MAF) Sensor
Output Circuit High Input1. Engine speed is between
600rpm and 5000rpm.
2. MAF sensor output is more
tha n 1378mg/strk (4JA1-TC)
o r 1784mg/strk (4JH1-TC).
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 P0100 (Symptom Code 7) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3

6E –130 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
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 P0100 (Symptom Code 7) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the MAF sensor or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Visually check the MAF sensor. Was the problem found? —Go to Step 11 Go to Step 6
6 Using the DVM and check the MAF sensor power supply circuit.
1. Ignition “On ”, engine “Off ”.
2. Disconnect the MAF & IAT sensor connector.
3. Check the circuit for short to battery voltage circuit.
Was the DVM indicated specified value?
Approx imately 5.0V Go to Step 11 Less than 1V:
Go to Step 7
More than
specified value: Go to Step 8
7 Repair the open circuit between the ECM and MAF sensor.
Was the problem solved?
— Verify repair Go to Step 8
Step Action Value(s) Yes No
92
88 83
2 3
4
5
C-116
C-57(B)
V
4
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83
4
C-116
C-57(B)

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –131
8 Using the DVM and check the MAF sensor power
supply circuit.
1. Ignition “Off ”, engine “Off ”.
2. Disconnect the MAF & IAT sensor connector and ECM connector.
3. Check the circuit for short to MAF sensor +12V supply circuit.
Was the DVM indicated specified value?
No continuity Go to Step 10Go to Step 9
9 Repair the circuit for short to MAF sensor +12V supply circuit.
Is the action complete? —Verify repair —
10 Repair the short to battery voltage circuit between the ECM and MAF sensor.
Was the problem solved?
— Verify repair Go to Step 13
11 Substitute a known good MAF & IAT sensor assembly and recheck.
Was the problem solved? —Go to Step 12 Go to Step 13
12 Replace the MAF & IAT sensor assembly. Is the action complete? —Verify repair —
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
4
2
C-116
83
4
C-116
C-57(B)

6E –132 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0100 (Symptom Code 9) (Flash Code 65)
Mass Air Flow (MAF) Sensor Voltage Supply Circuit Low Input
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go 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 P0100 (Symptom Code 9) stored as
“ Present Failure ”? —Go to Step 3 Refer 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 P0100 (Symptom Code 9) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the MAF sensor or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Visually check the MAF sensor. Was the problem found? —Go to Step 10 Go to Step 6
6 Using the DVM and check the MAF sensor power supply circuit.
1. Ignition “On ”, engine “Off ”.
2. Disconnect the MAF & IAT sensor connector.
3. Check the circuit for short to ground circuit.
Was the DVM indicated specified value?
Approx imately 5.0V Go to Step 10Go to Step 7
92
88 83
2 3
4
5
C-116
C-57(B)
V
4
C-116

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E –133
7 Using the DVM and check the MAF sensor power
supply circuit.
1. Ignition “Off ”, engine “Off ”.
2. Disconnect the MAF & IAT sensor connector and ECM connector.
3. Check the circuit for short to MAF sensor ground circuit.
Was the DVM indicated specified value?
No continuity Go to Step 9Go to Step 8
8 Repair the circuit for short to MAF sensor ground. Is the action complete? —Verify repair —
9 Repair the short to ground circuit between the ECM and MAF sensor.
Was the problem solved?
— Verify repair Go to Step 12
10 Substitute a known good MAF & IAT sensor assembly and recheck.
Was the problem solved? —Go to Step 11 Go to Step 12
11 Replace the MAF & IAT sensor assembly. 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 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
4
3
C-116
83
4
C-116
C-57(B)

6E –134 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0100 (Symptom Code B) (Flash Code 65)
Mass Air Flow (MAF) Sensor Output Circuit Low Input
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check ”
performed?
— Go to Step 2 Go 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 P0100 (Symptom Code B) stored as
“ Present Failure ”? —Go to Step 3 Refer 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 P0100 (Symptom Code B) stored in this
ignition cycle? —Go to Step 4 Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the MAF sensor or ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
— Verify repair Go to Step 5
5 Visually check the MAF sensor. Was the problem found? —Go to Step 11 Go to Step 6
92
88 83
2 3
4
5
C-116
C-57(B)