Isuzu KB P190. Manual - part 428

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-95

DTC P0101 (Flash Code 92)

Circuit Description

The mass air flow (MAF) sensor is an air flow meter
that measures the amount of air that enters the engine.
It is fitted between the air cleaner and turbocharger. A
small quantity of air that enters the engine indicates
deceleration or idle speed. A large quantity of air that
enters the engine indicates acceleration or a high load
condition. The ECM will calculate a predicted MAF
value and compares the actual MAF sensor voltage
signal to the predicted MAF value. This comparison will
determine if the signal is stuck, or is too low or too high
for a given operating condition. If the ECM detects that
the actual MAF sensor signal voltage is not within a
predetermined range of the calculated MAF value, this
DTC will set.

Condition for Running the DTC

• DTCs P0045, P0102, P0103, P0107, P0108,

P0112, P0113, P0116, P0117, P0118, P0122,
P0123, P0234, P0403, P0404, P0405, P0406,
P0638, P0652, P0653, P0698, P0699, P1404,
P2100, P2101, P2103, P2227, P2228 and P2229
are not set.

AND following conditions are met longer than 10
seconds.

• The battery voltage is between 10.0 to 16.0 volts.

• The ignition switch is ON.

• The intake air temperature is less than 110

°C

(230

°F).

• The engine coolant temperature is between 0 to

110

°C (32 to 230°F).

• The engine speed is between 850 to 3700 RPM.

• The EGR control is commanded OFF.

• The intake throttle control is commanded OFF.

• The commanded fuel injection quantity is OFF

(accelerator pedal is not depressed).

• The engine run time is longer than 5 seconds.

Condition for Setting the DTC

• The ECM detects that the MAF sensor signal

voltage is not within a predetermined range of the
calculated MAF value for longer than 10 seconds.

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM limits fuel injection quantity.

• The ECM inhibits pilot injection.

• The ECM inhibits EGR control.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• Any unmetered air that enters the engine

downstream of the MAF sensor will cause this
DTC to set.

• High resistance in the MAF sensor circuit will set

this DTC.

• A short between the signal circuit of the MAF

sensor and the signal circuit of the intake air
temperature (IAT) sensor will skew the MAF
sensor lower than normal at higher air flows.

Notice:

• The MAF Sensor parameter on scan tool will only

update with engine running or one time after the
key is cycled when the ignition has been turned
OFF for longer than 10 seconds.

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P0101

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check -
Engine Controls

6E-96 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Inspect the following conditions:

• Restricted air cleaner element, restricted

or collapsed air tubing between the air
cleaner and the intake manifold

• Any air induction leak

• Any contamination or objects that block

the MAF sensor inlet

• Skewed or slow MAF sensor

• Any water intrusion in the induction

system

• Any type of restriction in the exhaust

system

• A sticking intake throttle valve

• A sticking EGR valve

• A sticking turbocharger nozzle control

actuator or solenoid valve

Repair or replace as necessary.

Did you find and correct the condition?

—

Go to Step 6

Go to Step 3

Turn OFF the ignition.

Disconnect the MAF sensor harness
connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the MAF sensor (pins 1, 2 and 3
of E-47).

Disconnect the ECM harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 40, 42 and 43 of
E-90).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 6

Go to Step 4

Test each sensor circuit between the ECM
(pins 40 and 43 of E-90) and the MAF sensor
(pins 2 and 3 of E-47) for high resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 6

Go to Step 5

Replace the MAF sensor. Refer to MAF Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 6

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 2

Go to Step 7

Step

Action

Value(s)

Yes

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-97

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

6E-98 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0102 or P0103 (Flash Code 91)

Circuit Description

• Ignition voltage circuit

• Low reference circuit

• MAF sensor signal circuit

The ECM monitors the MAF sensor signal voltage. This
output voltage will display on the scan tool as a voltage
parameter and as a grams per second (g/s) parameter.
If the ECM detects an excessively low or high signal
voltage, DTC P0102 or P0103 will set.

Condition for Running the DTC

• The battery voltage is between 11.5 to 16.0 volts.

• The ignition switch is ON.

• The engine is running.

Condition for Setting the DTC

• The ECM detects that the MAF sensor signal

voltage is less than 0.1 volts. (DTC P0102)

• The ECM detects that the MAF sensor signal

voltage is more than 4.9 volts for 3 seconds. (DTC
P0103)

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM uses a MAF substitution of default value.

• The ECM limits fuel injection quantity.

• The ECM inhibits pilot injection.

• The ECM inhibits EGR control.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

Notice:

• The MAF Sensor parameter on scan tool will only

update with engine running or one time after the
key is cycled when the ignition has been turned
OFF for longer than 10 seconds.

Test description

The number below refers to the step number on the
Circuit/ System Testing.
DTC P0102
4. This step tests for proper operation of the circuit in
the signal circuit. If the fuse in the jumper opens when
you perform this test, the signal circuit is shorted to
ground or low reference circuits.

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P0102

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check -
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check -
Engine Controls

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Observe the Mass Air Flow (MAF) Sensor
parameter with a scan tool.

Is the MAF Sensor parameter less than the
specified value?

0.1 volts

Go to Step 3

Go to Diagnostic

Aids

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