mass air flow ISUZU TF SERIES 2004 Repair Manual

6E-132 3.5L ENGINE DRIVEABILITY AND EMISSIONS 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
P0117 A Engine Coolant Temperature
Sensor Low Input ECT sensor output voltage is below 0.08V. ECT sensor output voltage is
more than 0.08V. 1. Sensor signal circuit short to ground circuit.
2. ECT sensor malfunction.
3. ECM malfunction. A21 -
14
P0118 A Engine Coolant Temperature
Sensor High Input ECT sensor output voltage is more than 4.8V. The ECM uses default engine
coolant temperature value
based on start-up ECT and
time from start.
ECT sensor output voltage is
below 4.8V. 1. Sensor signal circuit open or short to voltage
circuit.
2. Sensor ground circuit open or short to voltage
circuit.
3. Poor connector connection
4. ECT sensor malfunction.
5. ECM malfunction. A21/
A22 P0406
1. No DTC relating to barometer sensor, ECT
sensor, CMP sensor, CKP sensor, MAF
sensor and TPS (low input & high input).
2. Engine speed is more than 2000rpm.
3. Engine coolant temperature is more than
75
C.
4. TPS output voltage is between 0.24V and
0.26V. Above conditions are met for 3
seconds.
OR
P0121 A Throttle Position Sensor
Range/Performance
1. No DTC relating to barometer sensor, ECT
sensor, CMP sensor, CKP sensor, MAF
sensor and TPS (low input & high input).
2. Engine speed is below 3200rpm.
3. Engine coolant temperature is more than
75
C.
4. TPS output voltage is between 4.54V and
4.56V. Above conditions are met for 3
seconds. No fail-safe function. TPS output voltage is below
0.24V or more than 0.26V.
OR
TPS output voltage is below
4.54V or more than 4.56V. 1. TPS malfunction.
2. Sensor signal circuit short to voltage circuit.
3. Electrical interference.
4. ECM malfunction. B27/
B26/
B39 - P0122 A Throttle Position Sensor Low
Input TPS output voltage is below 0.24V. TPS output voltage is more
than 0.24V. 1. Sensor power supply circuit open or short to
ground circuit.
2. Sensor signal circuit open or short to ground
circuit.
3. Poor connector connection.
4. TPS malfunction.
5. ECM malfunction. B27/
B26 P0336/
P0337
or
P0342
21
P0123 A Throttle Position Sensor High
Input TPS output voltage is more than 4.56V. The ECM uses default throttle
position value based on mass
air flow and engine speed.
TPS output voltage is below
4.56V. 1. Sensor power supply circuit short to voltage
circuit.
2. Sensor signal circuit short to voltage circuit.
3. Sensor ground circuit open or short to voltage
circuit.
4. Poor connector connection.
5. TPS malfunction.
6. ECM malfunction. B27/
B26/
B39 P0103/
P0113/
P0341/
P0342

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-143
An open or short to voltage circuit in the sensor ground circuit between the ECM terminal B39 and splice will cause
one or more of following DTCs to be set:





P0103 (Flash Code 61): Mass Air Flow Sensor Circuit High Input





P0113 (Flash Code 23): Intake Air Temperature Sensor High Input





P0123 (Flash Code 21): Throttle Position Sensor High Input





P0341(Flash Code 41): Camshaft Position Sensor Circuit Range/Performance





P0342 (Flash Code 41): Camshaft Position Sensor Circuit No Signal

An open circuit in the sensor power supply circuit between the ECM terminal B27 and splice will cause one or more of
following DTCs to be set:





P0122 (Flash Code 21): Throttle Position Sensor Low Input





P0342 (Flash Code 41): Camshaft Position Sensor Circuit No Signal

A short to ground circuit in the sensor power supply circuit between the ECM terminal B27 and splice will cause one
or more of following DTCs to be set:





P0122 (Flash Code 21): Throttle Position Sensor Low Input





P0336 (Flash Code 29): Crankshaft Position Sensor Circuit Range/Performance (58X)





P0337 (Flash Code 29): Crankshaft Position Sensor Circuit No Signal (58X)

A short to ground circuit in the sensor signal circuit between the ECM terminal B28 and sensor will cause one of
following DTC to be set:





P0337 (Flash Code 29): Crankshaft Position Sensor Circuit No Signal (58X)


RUW46EMF000101

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-145
DIAGNOSTIC TROUBLE CODE (DTC) P0101 (FLASH CODE 61) MASS AIR
FLOW SENSOR CIRCUIT RANGE/PERFORMANCE

RUW46EMF000101

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)
61 P0101 B Mass Air Flow Sensor
Circuit
Range/Performance
1. No DTC relating to barometer sensor, TPS, CMP sensor, CKP sensor and MAF sensor (low input & high input).
2. Engine speed is between 2800rpm and 4500rpm.
3. Throttle position sensor output voltage is between 1V and 3V.
4. Intake air temperature is between -14
C and 70
C.
5. Air flow amount below 0.04g/s (small air) or more than 177g/s (large air).
Above conditions are met for 3 seconds.
No fail-safe function.

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-147
Step Action Value (s) Yes No
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 Go to Step 6
6
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?


 E-61(B)
E-63






- Verify repair Go to Step 7
7
Remove the MAF & IAT sensor assembly and visually
check.
Was the problem found?
- Go to Step 11 Go to Step 8

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-149
DIAGNOSTIC TROUBLE CODE (DTC) P0102 (FLASH CODE 61) MASS AIR
FLOW SENSOR CIRCUIT LOW INPUT

RUW46EMF000101

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)
61 P0102 A Mass Air Flow Sensor
Circuit Low Input
MAF sensor output voltage is below 0.3V. The ECM uses default mass air flow
value based on IAC valve position,
throttle position, barometer pressure
and engine speed.

6E-150 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 of 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 5 to 8 g/s at idle to around
25 to 40 g/s at maximum engine load. DTC P0102 will
be set if the signal from the MAF sensor is below the
possible range of a normally operating MAF sensor.
.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connection.
 Misrouted harness – Inspect the MAF senso
r
harness to ensure that it is not routed too close to
high voltage wires.
 Damaged harness –Inspect the wiring harness fo
r
damage. If the harness appears to be OK, observe
the Tech 2 while moving connectors and wiring
harnesses related to the MAF sensor. A change in
the display will indicate the location of the fault.
If DTC P0102 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set


Diagnostic Trouble Code (DTC) P0102 (Flash Code 61) Mass Air Flow Sensor
Circuit Low Input
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 P0102 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 P0102 stored in this ignition cycle?
- Go to Step 4 Refer to
Diagnostic Aids
and Go to Step 4

6E-154 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0103 (FLASH CODE 61) MASS AIR
FLOW SENSOR CIRCUIT HIGH INPUT

RUW46EMF000101

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)
61 P0103 A Mass Air Flow Sensor
Circuit High Input
MAF sensor output voltage is more than 4.9V. The ECM uses default mass air flow
value based on IAC valve position,
throttle position, barometer pressure
and engine speed.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-155
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 of 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 5

8 g/s at idle to around
25 to 40 g/s at maximum engine load. DTC P0103 will
be set if the signal from the MAF sensor is above the
possible range of a normally operating MAF sensor.

DIAGNOSTIC AIDS
If DTC P0103 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.


Diagnostic Trouble Code (DTC) P0103 (Flash Code 61)
Mass Air Flow Sensor Circuit High Input
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 P0103 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 P0103 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?


 E-61(B)
E-63






- Verify repair Go to Step 5

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-183
DIAGNOSTIC TROUBLE CODE (DTC) P0122 (FLASH CODE 21) THROTTLE
POSITION SENSOR CIRCUIT LOW INPUT



RUW46EMF000101

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)
21 P0122 A Throttle Position
Sensor Low Input TPS output voltage is below 0.24V. The ECM uses default throttle
position value based on mass air
flow and engine speed.

CIRCUIT DESCRIPTION
The TPS circuit provides a voltage signal that changes
relative to throttle blade angle. The signal voltage will
vary from below 0.6 volts at closed throttle to about 4.5
volts at wide open throttle (WOT).
The TPS signal is used by the Engine Control Module
(ECM) for fuel control and many of the ECM-controlled
outputs.

DIAGNOSTIC AIDS
Check for the following conditions:
 Poor connection at ECM – Inspect harness
connectors for backed-out terminals, imprope
r
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connection.
 Damaged harness –Inspect the wiring harness fo
r
damage. 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.
If DTC P0122 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.