Isuzu D-Max / Isuzu Rodeo (TFR/TFS). Manual - part 839

6E–85

3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0103 (Flash DTC=61) MAF Sensor Circuit

High Frequency

060RW077

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 or 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 4 

∼

 7 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.

Conditions for Setting the DTC

D

The engine is running between 500 and 2000 RPM for
more than 2 seconds.

D

System voltage is above 5000m volts.

D

Above conditions present for at least 961m sec.

Action Taken When the DTC Sets

D

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

D

The ECM calculates an airflow value based on idle air
control valve position, throttle position, RPM and
barometric pressure.

D

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Conditions for clearing the MIL/DTC

D

The ECM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

D

A history DTC P0103 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0103 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.

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.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. This step verifies that the problem is present at idle.

4. A frequency reading with the MAF sensor connector

disconnected indicates an electromagnetic
interference (EMI) related fault.

6E–86

3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0103 – MAF Sensor Circuit  High Frequency

 

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

1. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “DTC” info for DTC P0103.

Does the Tech 2 indicate DTC P0103 failed this
ignition?

—

Go to 

Step 3

Refer to

Diagnostic

Aids

3

1. Start the engine.
2. With the engine idling, monitor “MAF Frequency”

display on the Tech 2.

Is “MAF Frequency” above the specified value?

25 to 40 g/s

Go to 

Step 4

Go to 

Step 7

4

1. Ignition “OFF.”
2. Disconnect the MAF sensor connector.
3. Ignition “ON,” engine idling.
4. Using a Tech 2, monitor “MAF Frequency.”

Does the Tech 2 indicate a “MAF Frequency” at the
specified value?

0 g/s

Go to 

Step 5

Go to 

Step 6

5

Replace the MAF sensor.

Is the action complete?

—

Verify repair

Go to 

Step 8

6

1. Check the MAF harness for incorrect routing near

high voltage components (solenoids, relays,
motors).

2. If incorrect routing is found,  correct the harness

routing.

Was a problem found?

—

Verify repair

Go to 

Step 6

7

1. With the engine idling, monitor “MAF Frequency”

display on the Tech 2.

2. Quickly snap open throttle to wide open throttle

while under a road load and record value.

Does the Tech 2 indicate “MAF Frequency” above the
specified value?

25 to 40 g/s

Go to 

Step 5

Go to 

Step 8

8

Replace the ECM.

Is the action complete?

—

Verify repair

—

6E–87

3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0107 (Flash DTC=33) BARO Sensor Circuit

Low Voltage

060RW072

Circuit Description

The barometric pressure (BARO) sensor responds to
changes in intake manifold pressure (vacuum).  The
BARO sensor signal voltage to the Engine Control
Module ECM varies from below 2 volts at idle (high
vacuum) to above 4 volts with the ignition “ON,” engine
not running or at wide-open throttle (low vacuum).
The ECM monitors the BARO signals for voltages outside
the normal range of the BARO sensor.  If the ECM detects
a BARO signal voltage that is excessively low, DTC
P0107 will be set.

Conditions for Setting the DTC

D

Ignition SW is ON.

D

Above conditions present for at least 19 second.

D

The BARO sensor voltage under 100m volts.

Action Taken When the DTC Sets

D

The ECM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

D

The ECM will default to a BARO value of 79.3 kpa.

D

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.

Conditions for Clearing the MIL/DTC

D

The ECM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

D

A history DTC P0107 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0107 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the ECM battery
feed.

Diagnostic Aids

Check for the following conditions:

D

Check for intermittent codes.

D

The BARO sensor shares a ground with the ECT
sensor, and the Transmission Fluid Temperature
sensor.

D

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.

D

Damaged harness – Inspect the wiring harness for
damage.  If the harness appears to be OK, observe the
BARO display on the Tech 2 while moving connectors
and wiring harnesses related to the sensor.  A change
in the display will indicate the location of the fault.

If DTC P0107 cannot be duplicated, the information
included in the Failure Records data can be useful in
determining vehicle mileage since the DTC was last set.

6E–88

3.2L ENGINE DRIVEABILITY AND EMISSIONS

If it is determined that the DTC occurs intermittently,

performing the DTC P0107 Diagnostic Chart may isolate
the cause of the fault.

DTC P0107 – BARO Sensor Circuit  Low Voltage

 

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to 

Step 2

Go to 

OBD

System

Check

2

1. Ignition “ON,” engine “OFF.”
2. With the throttle closed, observe the BARO value

displayed on the Tech 2.

Is the BARO value near the specified value?

11 kpa at sea

level

Go to 

Step 4

Go to 

Step 3

3

1. Ignition “ON,” engine “OFF.”
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “DTC” info for DTC P0107.

Does the Tech 2 indicate DTC P0107 failed?

—

Go to 

Step 4

Refer to

Diagnostic

Aids

4

1. Ignition “OFF.”
2. Disconnect the BARO sensor electrical connector.
3. Jumper the 5 volt reference “A” circuit and the

BARO signal together at the BARO sensor harness
connector.

4. Ignition “ON.”
5. Observe the BARO value displayed on the Tech 2.

Is the BARO value near the specified value?

5 V 104 kpa

Go to 

Step 10

Go to 

Step 5

5

1. Disconnect the jumper.
2. Connect a test light between B+ and the BARO

sensor signal circuit at the BARO sensor  harness
connector.

3. Observe the BARO value displayed on the Tech 2.

Is the BARO value near the specified value.

5 V 104 kpa

Go to 

Step 6

Go to 

Step 8

6

1. Ignition “OFF.”
2. Disconnect the ECM and check the 5 volt reference

“A” circuit for an open or short to ground.

3. If the 5 volt reference “A” circuit is open or shorted to

ground, repair it as necessary.

Was the 5 volt reference “A” circuit open or shorted to
ground?

—

Verify repair

Go to 

Step 7

7

Check the 5 volt reference “A” circuit for a poor
connection at the ECM and replace the terminal if
necessary.

Did the terminal require replacement?

—

Verify repair

Go to 

Step 11

8

1. Ignition “OFF.”
2. Disconnect the ECM, and check the BARO signal

circuit for an open, short to ground, or short to the
sensor ground circuit.

3. If the BARO sensor signal circuit is open or shorted

to ground, repair it as necessary.

Was the BARO signal circuit open or shorted to
ground?

—

Verify repair

Go to 

Step 9