2004 ISUZU TF SERIES oil

6E-122 3.5L ENGINE DRIVEABILITY AND EMISSIONS
A/C SYSTEM CIRCUIT DIAGNOSIS



RTW36EMF000101

CIRCUIT DESCRIPTION
When air conditioning and blower fan are selected, and
if the system has a sufficient refrigerant charge, a
12-volt signal is supplied to the A/C request input of the
Engine Control Module (ECM). The A/C request signal
may be temporarily canceled during system operation
by the electronic thermostat in the evaporator case. The
electronic thermostat may intermittently remove the
control circuit ground for the A/C thermostat relay to
prevent the evaporator from forming ice. When the A/C
request signal is received by the ECM, the ECM
supplies a ground from the compressor clutch relay i
f
the engine operating conditions are within acceptable
ranges. With the A/C compressor relay energized,
voltage is supplied to the compressor clutch coil.
The ECM will enable the compressor clutch to engage
whenever A/C has been selected with the engine
running, unless any of the following conditions are
present:

 The A/C request switch is "Off".
 The engine speed is lower than 550rpm or greate
r
than 6375rpm.
 The engine coolant temperature is greater than
120
.
DIAGNOSTIC AIDS
To diagnose an the intermittent fault, check for the
following conditions:
 Poor connection at the ECM–Inspect connections fo
r
backed-out terminals, 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. If the harness appears to OK, observe the
A/C clutch while moving connectors and wiring
harnesses related to the A/C. A sudden clutch
malfunction will indicate the source of the intermitten
t
fault.

6E-124 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
8
Check for poor/faulty connection at the A/C
compressor, A/C compressor relay or ECM connector.
If a poor/faulty connection is found, repair as
necessary.
Was the problem found?
E-2


X-14







E-61(B)



- Verify repair Go to Step 9
9
 Using the DVM and check the A/C compressor relay.
1. Ignition "Off", engine "Off".
2. Remove the A/C compressor relay from the relay
box.
3. Check the relay coil.
Was the DVM indicated specified value?
X-14






Approximately
140

Go to Step 10 Replace A/C
compressor relay
and verify repair
10
Using the DVM and check the A/C compressor relay
power supply circuit.
1. Ignition "On", engine "Off".
2. Remove the A/C compressor relay from the relay
box.
3. Check the circuit for open or short to ground circuit.
Was the DVM indicated specified value?
X-14





VV

10 – 14.5V Go to Step 12 Go to Step 11
11
Repair the open or short to ground circuit between the
"A/C" fuse (10A) and A/C compressor relay.
Is the action complete?
- Verify repair -

6E-126 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
15
Check for poor/faulty connection at the thermo relay,
triple pressure switch, thermostat or ECM connector. If
a poor/faulty connection is found, repair as necessary.
Was the problem found?
E-61(B)
X-15







C-24C-55









- Verify repair Go to Step 16
16
 Using the DVM and check the thermo relay.
1. Ignition "Off", engine "Off".
2. Remove the thermo relay from the relay box.
3. Check the relay coil.
Was the DVM indicated specified value?
X-15






Approximately
140

Go to Step 17 Replace thermo
relay and verify
repair
17
 Using the DVM and check the thermo relay power
supply circuit.
1. Ignition "On", engine "Off".
2. Remove the thermo relay from the relay box.
3. Check the circuit for open or short to ground circuit.
Was the DVM indicated specified value?
X-15





VV

10 – 14.5V Go to Step 19 Go to Step 18
18
Repair the open or short to ground circuit between the
"A/C" fuse (10A) and thermo relay.
Is the action complete?
- Verify repair -

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-137
Flash
Code Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up) Recovery Condition Related Failure Parts Related
ECM Pin
No. Related
Multiple
DTC
P0351 A Ignition 1 Control Circuit
A32 - P0352 A Ignition 2 Control Circuit
B7 - P0353 A Ignition 3 Control Circuit
A31 - P0354 A Ignition 4 Control Circuit
B8 - P0355 A Ignition 5 Control Circuit
A30 -
42
P0356 A Ignition 6 Control Circuit 1. No DTC relating to CMP sensor and CKP
sensor.
2. Engine speed is between 250rpm and 850
rpm.
3. 10 ignition signals are not detected
consecutively. Fuel cut is operated more than
2000rpm. 10 ignition signals are detected
consecutively. 1. Ignition coil harness open circuit, short to
ground or short to voltage.
2. Ignition coil malfunction.
3. ECM malfunction.
B9 -

6E-146 3.5L ENGINE DRIVEABILITY AND EMISSIONS
CIRCUIT DESCRIPTION
The mass air flow (MAF) sensor measures the amount
of air which passes through it into the engine during a
given time. The Engine Control Module (ECM) uses the
mass air flow information to monitor engine operating
conditions for fuel delivery calculations. A large quantity
of air entering the engine indicates an acceleration o
r
high load situation, while a small quantity or air indicates
deceleration or idle.
The MAF sensor produces a frequency signal which
can be monitored using a Tech 2. The frequency will
vary within a range of around 4 to 7 g/s at idle to around
25 to 40 g/s at maximum engine load. DTC P0101 will
be set if the signal from the MAF sensor does not match
a predicted value based on throttle position and engine
RPM.
DIAGNOSTIC AIDS
An intermittent may be caused by the following:
 Poor connections.
 Mis-routed harness.
 Rubbed through wire insulation.
 Broken wire inside the insulation.
Refer to Intermittents under service category
Symptoms.
Any un-metered air may cause this DTC to set. Check
for the following:
 The duct work at the MAF sensor for leaks.
 An engine vacuum leak.
 The PCV system for vacuum leaks.
 An incorrect PCV valve.
 The engine oil dip stick not fully seated.
 The engine oil fill cap loose or missing.


Diagnostic Trouble Code (DTC) P0101 (Flash Code 61)
Mass Air Flow Sensor Circuit Range/Performance
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 P0101 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 P0101 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-199
Step Action Value (s) Yes No
9
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 11 Go to Step 10
10
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 11
11
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 13 Go to Step 12
12
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
13
13
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 14 Refer to Injector
Coil Test &
Injecotr Balance
Test Procedure
14
Check for fuel pressure.
Refer to 6E-116 "Fuel System Diagnosis".
Was the fuel pressure correct?
- Go to Step 15 Refer to Fuel
System
Diagnosis
15
Replace the O2 sensor for the affected bank.
Was the problem solved?
- Verify repair Go to Step 16

6E-206 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
11
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 13 Go to Step 12
12
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
13
13
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 14 Refer to Injector
Coil Test &
Injector Balance
Test Procedure
14
Check for fuel pressure.
Refer to 6E-116 "Fuel System Diagnosis".
Was the fuel pressure correct?
- Go to Step 15 Refer to Fuel
System
Diagnosis
15
Replace the O2 sensor for the affected bank.
Was the problem solved?
- Verify repair Go to Step 16
16
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 17
17
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 -

6E-214 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%.
Was 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 11 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