check engine ISUZU TF SERIES 2004 Workshop Manual

6E-222 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Condition For Setting The DTC and Action Taken When The DTC Sets
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1171 D Fuel Supply System
Lean During Power
Enrichment (Bank 1) 44

P1172 D Fuel Supply System
Lean During Power
Enrichment (Bank 2) 1. No DTC relating to MAF sensor, IAT sensor, ECT sensor,
TPS, CMP sensor, CKP sensor, VSS, injector control
circuit, ignition control circuit, O2 sensor circuit low voltage
& high voltage (bank 1 & 2) and O2 sensor circuit no
activity (bank 1 & 2).
2. Engine speed is between 1000rpm and 6000rpm.
3. Intake air temperature is below 70
C.
4. Engine coolant temperature is between 30
C and 120
C.
5. Engine load is between 150 and 255.
6. Throttle position output is more than 2.22V and fluctuation
is below 0.28V.
7. Except fuel cut operation.
8. O2 sensor output voltage below 250mV for 10 seconds. No fail-safe function.


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 o
f
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. Unde
r
these conditions the ECM should detect a “rich"
condition (high oxygen sensor voltage). If this “rich"
exhaust is not detected at this time, a DTC P1171 o
r
P1172 will set. A plugged fuel filter, restricted fuel line,
restricted in-tank filter or defective fuel pump can
prevent adequate amouts of fuel from being supplied
during power enrichment mode.

DIAGNOSTIC AIDS
 A restricted fuel filter or fuel line, restricted in-tank
filter, or a defective fuel pomp may supply adequate
amounts of fuel at idle, but may not be able to supply
enough fuel during heavy acceleration.
 Water or alcohol in the fuel may cause low HO2S
voltage during acceleration.
 Check for faulty or plugged fuel injector(s).
 Check for low fuel.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-223
Diagnostic Trouble Code (DTC) P1171 (Flash Code 44) Fuel Supply System
Lean During Power Enrichment (Bank 1)
Diagnostic Trouble Code (DTC) P1172 (Flash Code 44) Fuel Supply System
Lean During Power Enrichment (Bank 2)
Step Action Value (s) Yes No
1
Was 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 By Priority" in "F0:
Diagnostic Trouble Code".
Is the DTC P1171 or P1172 stored as "Present
Failure"?
- Go to Step 3 Refer 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 and
clear the DTC information.
3. Operate the vehicle and monitor the "F5: Failed
This Ignition" in "F2: DTC Information"
Was the DTC P1171 or P1172 stored in this ignition
cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4
1. Using the Tech 2, ignition "On" and engine "On".
2. Monitor the "Mass Air Flow" in the data display.
Does the Tech 2 indicate correct "Mass Air Flow" as
shown in the following graph, when engine speed is
increasing little by little?
Characteris tic of MAF Sens or -Ref erence (No Engine Load)-
0 5 10 15 20 25 30 35 40 45 50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Eng i ne Speed ( r pm) ( T ech2 R eadi ng )
Mass Air Flow (g/s)
( T ec h2 R eadi ng)
- Go to Step 6 Go to Step 5
5
Remove the MAF & IAT sensor assembly and check
for the following conditions.

Objects blocking the air cleaner.

Objects blocking the MAF sensor.

Objects blocking the throttle valve.

Vacuum leaking at intake duct.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P0101 and Go to
Step 6

6E-224 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
6
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 8 Go to Step 7
7
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%.
Is the action complete?
- Verify repair -
8
Check for the following conditions.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P0121 and Go to
Step 9
9
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"IAC Control" in the "IAC System".
3. Operate the Tech 2 in accrodance with procedure.
Was the engine speed changed, when the IAC Valve
is operating step by step?
-
Go to Step 10
Go to Step 10
10
Check for the following conditions.

Objects blocking the IAC Valve.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found?
- Verify repair Refer to DTC
P1508/P1509
and Go to Step
11
11
Check for injector for the affected bank.
Refer to 6E-106 "Injector Coil Test & Injector Balance
Test Procedure".
Was the injector operation correct?
- Go to Step 12 Refer to Injector
Coil Test &
Injector Balance
Test Procedure
12
Check for fuel pressure.
Refer to 6E-116 "Fuel System Diagnosis".
Was the fuel pressure correct?
- Go to Step 13 Refer to Fuel
System
Diagnosis
13
Replace the O2 sensor for the affected bank.
Was the problem solved?
- Verify repair Go to Step 14
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

6E-228 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0201 (Flash Code 31) Injector 1
Control Circuit
Diagnostic Trouble Code (DTC) P0202 (Flash Code 31) Injector 2
Control Circuit
Diagnostic Trouble Code (DTC) P0203 (Flash Code 31) Injector 3
Control Circuit
Diagnostic Trouble Code (DTC) P0204 (Flash Code 31) Injector 4
Control Circuit
Diagnostic Trouble Code (DTC) P0205 (Flash Code 31) Injector 5
Control Circuit
Diagnostic Trouble Code (DTC) P0206 (Flash Code 31) Injector 6
Control Circuit

Step Action Value (s) Yes No
1
Was 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 By Priority" in "F0:
Diagnostic Trouble Code".
Is the DTC P0201, P0202, P0203, P0204, P0205 or
P0206 stored as "Present Failure"?
- Go to Step 3 Refer 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 and
clear the DTC information.
3. Operate the vehicle and monitor the "F5: Failed
This Ignition" in "F2: DTC Information"
Was the DTC P0201, P0202, P0203, P0204, P0205 or
P0206 stored in this ignition cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-229
Step Action Value (s) Yes No
4
Check for poor/faulty connection at the injector or
ECM connector. If a poor/faulty connection is found,
repair as necessary.
Was the problem found?
E-61(B)



E-60(A)


E-6/E-7/E-8/E-9/
E-51/E-52


- Verify repair Go to Step 5
5
Visually check the injector for affected cylinder.
Was the problem found?
- Go to Step 11 Go to Step 6
6
Using the DVM and check the injector coil.
1. Ignition "Off", engine "Off".
2. Disconnect injector connector for the affected
cylinder.
3. Measure the resistance of injector coil.
Does the tester indicate standard resistance?








 
Injector


Approximately
15 at 20C
Go to Step 7
Go to Step 11

6E-230 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
7
Using the DVM and check the injector power supply
circuit.
1. Ignition "On", engine "Off".
2. Disconnect the injector connector for the affected
cylinder.
3. Check the circuit for open circuit.
Was the DVM indicated specified value?
E-6/E-7/E-8/E-9/
E-51/E-52
V



Battery voltage
Go to Step 9
Go to Step 8
8
Repair the open or short to ground circuit between the
ECM main relay and injector for the affected cylinder.
Is the action complete?
- Verify repair -
9
Using the DVM and check the injector signal circuit.
Breaker box is available:
1. Ignition "Off", engine "Off".
2. Install the breaker box as type A (ECM
disconnected).
Refer to 6E-95 page.
3. Disconnect the injector connector for the affected
cylinder.
4. Check the circuit for open or short to ground circuit.
Was the problem found?
A36
Breaker Box


E-6


No.1 Cylinder

B3
Breaker Box


E-7


No.2 Cylinder

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-231
Step Action Value (s) Yes No

A35
Breaker Box


E-8


No.3 Cylinder

B4
Breaker Box


E-9


No.4 Cylinder

A34
Breaker Box


E-51


No.5 Cylinder

B5
Breaker Box


E-52


No.6 Cylinder


Breaker box is not available:
1. Ignition "Off", engine "Off".
2. Disconnect the injector connector for the affected
cylinder and ECM connector.
3. Check the circuit for open or short to ground circuit.
Was the problem found?
E-60(A)
E-6






 No.1 Cylinder

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-233
Step Action Value (s) Yes No
10 Using the DVM and check the injector signal circuit.
1. Ignition "On", engine "Off".
2. Disconnect the injector connector for the affected
cylinder.
3. Check the circuit for short to battery voltage circuit.
Was the DVM indicated battery voltage?
E-6/E-7/E-8/E-9/
E-51/E-52
V



- Repair faulty
harness and
verify repair Go to Step 12
11
Replace the injector for the affected cylinder.
Was the problem solved?
- Verify repair Go to Step 12
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 -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-235
CIRCUIT DESCRIPTION
The CKP reference signal is produced by the crankshaft
position (CKP) sensor. During one crankshaft
revolution, crankshaft pulses will be produced. The
Engine Control Module (ECM) uses the CKP reference
signal to calculate engine RPM and crankshaft position.
The ECM constantly monitors the number of pulses on
the CKP reference circuit and compares them to the
number of camshaft position (CMP) signal pulses being
received. If the ECM receives an incorrect number o
f
pulses on the CKP reference circuit, DTC P0336 will
set.

DIAGNOSTIC AIDS
An intermittent may be caused by a poor connection,
rubbed–through wire insulation or a wire broken inside
the insulation. Check for:
 Poor connection –Inspect the ECM harness and
connectors for improper mating, broken locks,
improperly formed or damaged terminals, and poo
r
terminal-to-wire connection.
 Damaged harness – Inspect the wiring harness fo
r
damage.
Reviewing the Failure Records vehicle mileage since
the diagnostic test last failed may help determine ho
w
often the condition that caused the DTC to be set
occurs. This may assist in diagnosing the condition.

Diagnostic Trouble Code (DTC) P0336 (Flash Code 29) Crankshaft Position
Sensor Circuit Range/Performance (58X)
Diagnostic Trouble Code (DTC) P0337 (Flash Code 29) Crankshaft Position
Sensor Circuit No Signal (58X)

Step Action Value (s) Yes No
1
Was 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 By Priority" in "F0:
Diagnostic Trouble Code".
Is the DTC P0336 or P0337 stored as "Present
Failure"?
- Go to Step 3 Refer 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 and
clear the DTC information.
3. Operate the vehicle and monitor the "F5: Failed
This Ignition" in "F2: DTC Information"
Was the DTC P0336 or P0337 stored in this ignition
cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4
4
Check any accessory parts which may cause electric
interference or magnetic interference.
Was the problem found?
- Remove the
accessory parts
and verify repair Go to Step 5
5
Attempt to start the engine.
Does the engine start and continue to "Run"?
- Go to Step 6 Go to Step 7

6E-236 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
6

Using the DVM and check the CKP sensor signal.
1. Ignition "On", engine "On".
2. Measure the CKP output voltage at the sensor and
ECM.
Does the tester indicate standard voltage?

Measurement Point Voltage (V) (AC Range)
At CKP sensor terminal 3 & GND
At ECM E60 connector A23 & GND
Approximately 1.9 V at 2000rpm

If a oscilloscope is available, monitor the CKP sensor
signal.
Does the oscilloscope indicate correct wave form?
Crankshaft Position (CKP) Sensor Reference Wave Form
0V


Measurement Terminal: A23(+) A25(-)
Measurement Scale: 2.0V/div 5ms/div
Measurement Condition: Approximately 2000rpm

Go to Step 17 Go to Step 7
7
Check for poor/faulty connection at the CKP sensor or
ECM connector. If a poor/faulty connection is found,
repair the faulty terminal.
Was the problem found?
E-60(A)





E-59





- Verify repair Go to Step 8