DTC P0101 - LLU
Diagnostic Instructions
DTC Descriptor
DTC P0101 00 : Mass Air Flow (MAF) Sensor
Performance
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Ignition Voltage
|
P0100 00
|
P0100 00
|
-
|
P0101 00
|
Signal Circuit
|
P0100 00
|
P0100 00, P0102 00
|
P0102 00
|
P0101 00
|
Ground
|
-
|
P0100 00, P0102 00
|
-
|
P0101 00
|
Typical Scan Tool Data
MAF Sensor
Circuit
|
Short to Ground
|
Open
|
Short to Voltage
|
Operating Conditions: Engine
running
Parameter Normal Range:
1 700-12 500 Hz
|
Ignition Voltage
|
65 535 Hz
|
65 535 Hz
|
-
|
Signal Circuit
|
65 535 Hz
|
65 535 Hz
|
65 535 Hz
|
Ground
|
-
|
65 535 Hz
|
-
|
Circuit/System Description
The mass air flow (MAF) sensor is integrated with the inlet
air temperature (IAT) sensor. The MAF sensor is an air flow
meter that measures the amount of air entering the engine. The
engine control module (ECM) uses the MAF sensor signal to
provide the correct fuel delivery for all engine speeds and loads.
The MAF/IAT sensor has the following circuits:
• |
MAF and IAT sensor ground |
The purpose of this diagnostic is to analyze the performance of
the MAF sensor by comparing the measured airflow to the following
2 distinct models:
• |
The first model is separated into two parts. The
first part is based on basic engine parameters and uses engine
speed, and throttle angle as inputs. The second part is derived
from long term fuel trim, at cruising speed and the ECM is looking
for an adaptive value to be within a calibrated range. |
• |
The second model uses the manifold absolute
pressure (MAP) sensor for input, and the ECM is looking for an
adaptation value to be within a calibrated range. |
Conditions for Running the DTC
• |
DTCs P0097 00, P0098 00,
P0100 00, P0102 00, P0103 00, P0121 00,
P0122 00, P0123 00, P0221 00, P0222 00,
P0223 00, P0237 00, P0238 00, P0335 00,
P0336 00, P2176 00, P2228 00, or P2229 00 are
not set. |
• |
The engine coolant temperature (ECT) is warmer
than 10°C (50°F). |
• |
The ignition voltage signal is greater than
9 V. |
• |
The change in the throttle position is less than
2 percent. |
• |
This DTC runs continuously within the enabling
conditions. |
Conditions for Setting the DTC
• |
The ECM detects that the measured MAF is not
within range of the calculated airflow based on throttle angle and
engine speed. |
• |
The ECM detects a significant error in the long
term fuel trim at cruising speed. |
• |
The ECM detects that the measured MAF is not
within range of the calculated model that is derived from MAP. |
Action Taken When the DTC Sets
• |
DTC P0101 00 is a Type B DTC. |
• |
The ECM will disable boost control and limit the
system to mechanical boost only, resulting in decrease in engine
power. |
• |
The ECM will switch to a default calculated MAF
sensor value based on engine speed and throttle position. |
Conditions for Clearing the DTC
DTC P0101 00 is a Type B DTC.
Diagnostic Aids
• |
The charge air cooler is connected to the
turbocharger and to the throttle body by flexible duct work that
requires the use of special high torque fastening clamps. These
clamps cannot be substituted. In order to prevent any type of air
leak when servicing the duct work, the tightening specifications
and proper positioning of the clamps is critical and must be
strictly adhered to. |
• |
Use a solution of soap and water in a spray bottle
to pinpoint any suspected air leaks in the induction system and in
the charge air cooler assembly. |
• |
A steady or intermittent high resistance of
15 Ω or greater on the ignition voltage circuit will cause the
MAF sensor signal to be increased by as much as 60 g/s. |
• |
Certain types of contaminants on the MAF sensor
heating elements act as a heat insulator, which will effect the
response of the sensor to airflow changes. This condition will
affect the long term fuel trim adaptation value. |
• |
Depending on the current ambient temperature, and
the vehicle operating conditions, a MAF sensor signal circuit that
is shorted to the IAT signal circuit will increase or decrease the
MAF sensor signal that is interpreted by the ECM. Additionally it
may cause a rapid fluctuation in the IAT Sensor parameter. |
• |
Inspect the harness of the MAF sensor to verify
that it is not routed too close to the following components: |
- |
The secondary ignition wires or coils |
• |
Inspect for any contamination, water intrusion, or
debris on the sensing elements of the MAF sensor. If debris is
present, clean the sensor. If the sensor cannot be cleaned, replace
the sensor. |
• |
A high resistance may cause a driveability concern
before this DTC sets. |
• |
Certain aftermarket air filters may cause this DTC
to set. |
• |
Certain aftermarket air induction systems may
cause this DTC to set. |
• |
Modifications to the air induction system may
cause this DTC to set. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
EL 38522 Variable Signal Generator
For equivalent regional tools, refer to
Special Tools .
Circuit/System Verification
- Verify that restrictions do not exist in the exhaust
system. Refer to
Restricted Exhaust .
- Verify that an exhaust leak does not exist, including
the mating surface area between the turbocharger and the exhaust
manifold.
- Ignition OFF for 90 seconds, determine the
current vehicle testing altitude.
- Ignition ON, engine OFF, observe the scan tool BARO
parameter, Boost Pressure Sensor parameter, and MAP Sensor
parameter. Compare the parameters to the
Altitude Versus Barometric Pressure table. The parameters
should be within the specified range indicated in the table.
- Engine operating at idle, observe the scan tool MAF
Sensor parameter. The reading should be between
1 700-3 200 Hz.
- A wide open throttle (WOT) acceleration from a stop
should cause the MAF sensor parameter on the scan tool to increase
rapidly. This increase should be from 2-6 g/s at idle to
greater than 200 g/s.
- Operate the vehicle within the conditions for running
the DTC to verify the DTC does not reset. You may also operate the
vehicle within the conditions that you observed from the freeze
frame/failure records data.
Circuit/System Testing
- Verify the integrity of the entire air induction
system including all turbocharger components by inspecting for the
following conditions:
• |
Loose or improper installation |
• |
An air flow restriction |
• |
A turbocharger air leak |
• |
Improperly routed vacuum hoses |
• |
In cold climates, inspect for any snow or ice
buildup |
• |
Inspect the MAF sensor elements for
contamination |
- Ignition OFF, disconnect the harness connector at the
B75B Mass Air Flow/Intake Air Temperature Sensor.
- Ignition OFF for 90 seconds, test for less than
5 Ω between the ground circuit terminal 2 and
ground.
⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
- Ignition ON, verify that a test lamp illuminates
between the ignition circuit terminal 4 and ground.
⇒ |
If the test lamp does not illuminate, test the
ignition circuit for a short to ground or an open/high resistance.
If the circuit tests normal and the ignition circuit fuse F16
is open, test all the components connected to the ignition circuit
and replace as necessary. |
- Test for 4.8-5.2 V between the signal circuit
terminal 5 and the ground circuit terminal 2.
⇒ |
If less than the specified range, test the signal
circuit for an open/high resistance or a short to ground. If the
circuit/connections test normal, replace the K20 Engine
Control Module. |
⇒ |
If greater than the specified range, test the
signal circuit for a short to voltage. If the circuit/connections
test normal, replace the K20 Engine Control Module. |
- Ignition OFF, connect the red lead of the
EL 38522 Variable Signal Generator to the signal
circuit terminal 5 at the B75B Mass Air Flow/Intake Air
Temperature Sensor harness connector. Connect the battery voltage
supply to B+, and ground the black lead.
- Set the EL 38522 Variable Signal
Generator switch to 5 V, the Frequency switch to 5 K, and
the Duty Cycle switch to Normal.
- Engine Idling, observe the scan tool MAF Sensor
frequency parameter. The parameter should be between
4 950-5 025 Hz.
⇒ |
If the parameter is not within the specified
range, replace the K20 Engine Control Module. |
- If all circuits/connections test normal, replace the
B75B Mass Air Flow/ Inlet Air Temperature Sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|