Dtc P0101 - Maf System Performance - Isuzu Trooper 1999 Workshop Manual

f The duct work at the MAF sensor for leaks.
f An engine vacuum leak.
f The PCV system for vacuum leaks.
f An incorrect PCV valve.
f The engine oil dip stick not fully seated.
f The engine oil fill cap loose or missing.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 1. Ignition "OFF."
2. Disconnect the Mass Air Flow (MAF) Sensor
harness connector from the MAF Sensor.
3. Place an unpowered test lamp between the 12 volt
signal circuit and the ground circuit, both at the MAF
Sensor connector.
4. Ignition "ON," Engine"OFF."
Did the test lamp illuminate?
3 1. Ignition "ON," Engine "OFF."
2. Using a Digital Voltmeter (DVM), check the 12 volt
signal circuit for the correct voltage.
Did the DVM indicate a value within the following
range?
4 1. Ignition "OFF."
2. Check the 12 volt signal circuit for the following
conditions:
f
An open circuit
f
A short to ground
Was the problem found?
5 Check the MAF ground circuit for the following
conditions:
f
An open circuit
f
A short to voltage
Was a problem found?
6 1. Ignition "OFF."
2. Check the MAF Sensor signal circuit between the
PCM and the MAF Sensor for the following
conditions:
f
An open circuit
f
A short to ground
f
A short to battery voltage
Was a problem found?
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0101 – MAF System Performance
Action
2. The MAF system performance or "rationality"
diagnostic uses the MAP sensor signal along with
other input to calculate an expected airflow rate that
is then compared to the actual measured airflow
from the MAF sensor. The first few steps of this
table verify that the MAP sensor is working properly.
6. Verifies the signal circuit from the MAF sensor
electrical connector to the PCM.
Verifies whether a ground and B+ circuit is
available.
Value(s)
Go to Step 2
—
Go to Step 6
—
11.5 to 12.5
Volt Go to Step 5
— Verify repair
— Verify repair
— Verify repair
6E–121
Yes No
Go to OBD
System
Check
Go to Step 3
Go to Step 4
—
—
Go to Step 7