FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Chevy Truck >> 2012 >> Express 3500 V8-6.6L DSL Turbo >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0101

P0101




DTC P0101

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0101

-
Mass Air Flow (MAF) Sensor Performance

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The mass air flow (MAF) sensor is integrated with the intake air temperature (IAT) sensor 1. 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 as an input when calculating the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition.

The ECM monitors the exhaust gas recirculation (EGR) flow when the EGR valve is commanded ON. The ECM compares the desired MAF to the actual MAF, if the difference is less than or greater than a calibrated threshold level the amount of detected EGR flow is out of range and an EGR DTC will set.

The ECM applies 5 V to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet airflow through the sensor bore. The frequency varies in a range of approximately 2,300 Hz at idle to near 9,000 Hz at maximum engine load, depending on engine coolant temperature (ECT).

When the EGR valve is commanded ON a lower frequency and g/s value will be indicated for the scan tool MAF parameters. Rich Idle is enabled by the ECM based on ECT and Ambient Air Temperature. The ECM calculates the Ambient Air Temperature based on the IAT Sensor 1 signal.





Conditions for Running the DTC

* DTCs P008F, P0102, P0103, P0106, P0112, P0113, P0128, P0403, P046C, P111C, P111D, P140F, P2598, P2599, or P268A are not set.

* The Ambient Air Temperature is between -7 and 52°C (+19.4 and 126°F).

* The ECT is between 70 and 123°C (158 and 253°F).

* The manifold absolute pressure (MAP) is between 75 and 280 kPa.

* The BARO is greater than 75 kPa.

* The engine run time is at least 90 s.

* The engine speed is less than 3,100 RPM.

* The EGR valve is closed.

* The Intake Air Flow (IAF) Valve Position is less than 5 %.

* The calculated fuel rate is between 5 mm3 and 70 mm3.

* The ignition voltage is at least 11 V.

* This DTC runs continuously when the enabling conditions are met for 10 s.

Conditions for Setting the DTC

The ECM detects that the MAF sensor air flow ratio is not within a predetermined range of the calculated MAF air flow ratio for greater than 10 s.

Action Taken When the DTC Sets

* DTC P0101 is a Type B DTC.

* Diesel particulate filter (DPF) regeneration is inhibited.

* EGR is inhibited.

Conditions for Clearing the DTC

DTC P0101 is a Type B DTC.

Diagnostic Aids

* A slight to moderate resistance of 10-20 ohms on the MAF sensor ignition voltage circuit may cause this DTC to set.

* Certain aftermarket air filters may cause this DTC to set.

* Certain aftermarket air induction systems may cause this DTC to set.

* Modifications the air induction system may cause this DTC to set.

* An inaccurate MAF sensor, an intake air flow restriction, any unmetered air that enters the engine downstream of the MAF sensor, or an air induction leak may cause this DTC to set.

* An aftermarket exhaust system may reduce engine back-pressure excessively and cause this DTC to set.

* A faulty EGR valve that does not close or open fully, may set this DTC.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Special Tools

J 38522 - Variable Signal Generator

For equivalent regional tools, refer to Special Tools Tools and Equipment.

Circuit/System Verification

1. Verify that DTCs P0102, P0103, P0106, P0403, or P046C are not set.

• If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

2. Ignition ON, observe the scan tool MAP and BARO parameters. The MAP and BARO parameters should be within 4 kPa of each other.

• If greater than the specified range, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for DTC P0106 for further diagnosis.

3. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust Restricted Exhaust.

4. Verify that leaks do not exist in the exhaust system. Refer to Exhaust Leakage Exhaust Leakage.

5. Engine idling, observe the scan tool MAF Sensor parameter. The reading should be between 10-40 g/s depending on the ECT temperature.

6. A WOT acceleration from a stop should cause the MAF Sensor parameter on the scan tool to increase rapidly. This increase should be from 10-40 g/s at idle to greater than 400 g/s at the time of the 1-2 shift.

7. Operate the vehicle within the Conditions for Running the DTC to verify that 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

Note:

* You must perform the Circuit/System Verification before proceeding with the Circuit/System Testing.

* You must perform the Repair Verification after completing the Circuit/System Testing.

1. Inspect for the following conditions:

* A dirty or deteriorating air filter element

* A leaking, loose, disconnected, or cracked positive crankcase ventilation (PCV) valve, pipe, or seal

* A loose or disconnected charge air cooler hose or pipe

* A restricted or collapsed air intake duct

* A misaligned or damaged air intake duct

* Any objects blocking the air inlet probe of the MAF/IAT sensor

* Any contamination or debris on the sensing elements in the probe of the MAF/IAT sensor

* A cracked or damaged MAF sensor housing

* Any water intrusion in the induction system

* Any snow or ice build-up at the air cleaner, MAF or MAP sensors in cold climates

* An intake manifold leak

* A MAP sensor seal that is leaking, missing, or damaged

* An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing

• If you find any of the above conditions, repair as necessary.

2. Ignition OFF, disconnect the harness connector at the B75B MAF/IAT sensor.

3. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the MAF low reference circuit terminal E and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

4. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 ohms between the IAT sensor 1 low reference circuit terminal A and ground.

• If greater than the specified range, test the IAT sensor 1 low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.

5. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal D and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

6. Ignition ON, test for 4.8-5.2 V between the MAF sensor circuit terminal C and ground.

• If less than the specified range, test the MAF sensor circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

• If greater than the specified range, test the MAF sensor circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.

7. Ignition OFF, connect the harness connector at the B75B MAF/IAT sensor.

8. Engine idling at operating temperature, perform the following:

1. Command the EGR solenoid to 0 % with a scan tool.

2. Observe the Airflow Leak Equivalence Ratio parameter for 10 s. The value should be between 0.8:1 and 1.2:1.

3. Observe the Airflow Leak Equivalence Ratio parameter while slowly increasing the engine speed until reaching wide open throttle (WOT). After 10 s, the value should stabilize and be between 0.8:1 and 1.2:1.

• If not within the specified range, test the charge air cooler system and air inlet system for leaks. Perform the Full System Air Leak Test and the Induction System Smoke Test. Refer to Charge Air Cooler Diagnosis (Full System Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test)Charge Air Cooler Diagnosis (Induction System Smoke Test) Charge Air Cooler Diagnosis (Induction System Smoke Test). If no air leaks are found, test all of the MAF sensor circuits for high resistance.

9. Visually inspect the EGR valve and verify the valve is in the closed position. Refer to Exhaust Gas Recirculation Valve Replacement Exhaust Gas Recirculation Valve Replacement.

• If the EGR valve is not in the closed position, replace the EGR valve and gaskets.

10. Ignition OFF, disconnect the harness connector at the B75B MAF/IAT sensor.

11. Ignition OFF, connect the red lead of the J 38522 - generatorto the MAF signal circuit terminal C at the B75B MAF/IAT sensor harness connector. Connect the battery voltage supply to B+. Connect the black lead to ground.

12. Set the J 38522 - generatorsignal switch to 5 V, the frequency to 5K, and the Duty Cycle to Normal.

13. Engine idling, observe the scan tool MAF Sensor parameter. The scan tool MAF Sensor parameter should be between 4,950-5,050 Hz.

• If the MAF Sensor parameter is not within the specified range, replace the K20 ECM.

14. If all circuits test normal, test or replace the B75B MAF/IAT sensor.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Perform the scan tool Diesel Particulate Filter (DPF) Regeneration Enable Diesel Particulate Filter (DPF) Regeneration Enable procedure if the DPF Soot Mass is less than 30 g. If the scan tool DPF Soot Mass is 30 g or greater, perform the Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration procedure.

* Mass Airflow Sensor with Intake Air Temperature Sensor Replacement Mass Airflow Sensor with Intake Air Temperature Sensor Replacement

* Control Module References Control Module References for ECM replacement, setup, and programming

pro multis Credits:Operation CHARM About Operation CHARM