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 2. 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 ECT reaches 60°C (140°F) the ECM can command the exhaust gas recirculation (EGR) valve ON, and a lower frequency and g/s value will be indicated on the scan tool.
The scan tool Air Leak Equivalence Ratio parameter is calculated by dividing the mass air flow sensor signal reading, by the estimated air flow.
The estimated air flow is based on the following signal readings:
* Engine speed
* Boost pressure
* IAT sensor 3
When the EGR valve is closed, the ideal air leak equivalence ratio is 1.0:1; the normal range is between 0.8:1 and 1.2:1.
A scan tool Air Leak Equivalence Ratio parameter greater than 1.2:1 may indicate:
* A leak before the turbocharger
* An inaccurate boost pressure sensor
* An inaccurate IAT sensor 3
* A skewed MAF sensor when the EGR valve is commanded closed
* A leaking EGR valve
A scan tool Air Leak Equivalence Ratio parameter less than 0.8:1 may indicate:
* A leak after the turbocharger
* An inaccurate boost pressure sensor
* An inaccurate IAT sensor 3
* A skewed MAF sensor when the EGR valve is commanded closed
* A leaking positive crankcase valve (PCV) system
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 determines that the Air Leak Equivalence Ratio is not within a predetermined range for greater than 10 s when the EGR valve is commanded closed.
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 inaccurate IAT sensor 3 may cause this DTC to set.
* The IAT sensor 3 is located before the inlet to the CAC. The IAT sensor 3 is also known as the CAC Inlet Temperature Sensor (Turbocharger).
* 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.
* The ECM calculates the Air Leak Equivalence Ratio differently for the LGH & LML RPO diesel engines, than it does for the LMM RPO diesel engines.
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
EN 38522 - Variable Signal Generator
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Circuit/System Verification
Note:
* To minimize the effects of residual engine heat, perform Steps 1 and 2 of this verification procedure only if the ignition has been OFF for 8 hours or more.
* The vehicle sitting in direct sun light or having the block heater ON will skew the results.
1. Ignition ON.
2. Verify the following scan tool parameters are within 35°C (63°F) of each other.
* CAC temperature sensor
* IAT Sensor 3 sensor
• If not within 35°C (63°F)
Refer to DTC P00EA or P00EB P00EA for further diagnosis.
• If within 35°C (63°F)
3. Engine idling.
4. Verify the scan tool IAT Sensor 3 sensor parameter is between -39 to +213°C (-38 to +415°F)
• If not between -39 to +213°C (-38 to +415°F)
Refer to DTC P00EA or P00EB P00EA for further diagnosis.
• If between -39 to +213°C (-38 to +415°F)
5. Engine running at a warm stabilized idle, 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 stable after 10 s and between 0.8:1 and 1.2:1.
Refer to Circuit/System Testing
• If stable after 10 s and between 0.8:1 and 1.2:1.
6. Ignition ON.
7. Verify that DTCs P0102, P0103, P0106, P0403, or P046C are not set.
• If a DTC sets
If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If no DTC sets.
8. Ignition ON, verify the scan tool MAP Sensor and BARO Sensor parameters are within 4 kPa of each other.
• If not within 4 kPa.
If greater than the specified range, refer to DTC P0106 P0106 for further diagnosis.
• If within 4 kPa.
9. Verify that restrictions do not exist in the exhaust system. Refer to Restricted Exhaust Testing and Inspection.
10. Verify that leaks do not exist in the exhaust system. Refer to Exhaust Leakage Testing and Inspection.
11. Engine idling.
12. Verify the scan tool MAF Sensor parameter is between 10-40 g/s, depending on the ECT temperature and EGR valve position.
• If not between 10-40 g/s
Refer to Circuit/System Testing.
• If between 10-40 g/s
13. Perform a scan tool snap shot to record MAF Sensor parameters. Safely perform a wide open throttle (WOT) acceleration from a stop through the time of the 1-2 shift.
14. Verify the snap shot scan tool MAF Sensor parameter increases 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.
• If the MAF Sensor parameter does not respond as specified
Refer to Circuit/System Testing.
• If the MAF Sensor parameter does respond as specified
15. 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 data.
16. Verify a DTC does not set.
• If the DTC sets
Refer to Circuit/System Testing.
• If the DTC does not set
17. All OK.
Circuit/System Testing
Note:
* You must perform the Circuit/System Verification before proceeding with the Circuit/System Testing.
* You must perform the Diagnostic Repair Verification after completing the Circuit/System Testing.
1. Verify none of the following conditions exist:
* 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 Mass Air Flow/Intake Air Temperature sensor
* Any contamination or debris on the sensing elements in the probe of the Mass Air Flow/Intake Air Temperature sensor
* A cracked or damaged mass air flow sensor housing
* Any water intrusion in the induction system
* Any snow or ice build-up at the air cleaner, mass air flow or manifold absolute pressure sensors in cold climates
* An intake manifold leak
* A manifold absolute pressure sensor seal that is leaking, missing, or damaged
* An Intake Manifold Resonator with a leaking seal, or a cracked or broken housing
* A restriction in the exhaust system. Refer to Restricted Exhaust Testing and Inspection.
* A leak in the exhaust system. Refer to Exhaust Leakage Testing and Inspection.
• If a condition exists
Repair as necessary.
• If no condition exists
2. Engine idling at operating temperature.
1. Command the EGR solenoid to 0 % with a scan tool.
2. Observe the Airflow Leak Equivalence Ratio parameter for 10 s. Verify the parameter stabilizes after 10 s and is between 0.8:1 and 1.2:1.
3. Slowly increase the engine speed until reaching WOT.
4. Verify the Airflow Leak Equivalence Ratio parameter stabilizes after 10 s and is between 0.8:1 and 1.2:1.
• If not stable after 10 s and between 0.8:1 and 1.2:1.
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 stable after 10 s and between 0.8:1 and 1.2:1.
3. Verify the exhaust gas recirculation valve is in the closed position, by visual inspection. Refer to Exhaust Gas Recirculation Valve Replacement Exhaust Gas Recirculation Valve Replacement.
• If the exhaust gas recirculation valve is not closed.
Replace the exhaust gas recirculation valve and gaskets.
• If the exhaust gas recirculation valve is closed.
4. Ignition OFF, disconnect the harness connector at the (5 Pin) B75B Mass Air Flow/Intake Air Temperature sensor (IAT sensor 2).
5. 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 2 ohms between the mass air flow ground circuit terminal E and ground.
• If 2 ohms or greater
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open or high resistance in the circuit.
• If less than 2 ohms replace the K20 Engine Control Module.
• If less than 2 ohms
6. Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal D and ground.
• If the test lamp does not illuminate and the circuit fuse is good
1. Ignition OFF, remove the test lamp and remove the fuse for the ignition voltage circuit.
2. Test for less than 2 ohms in the ignition voltage circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.
• If the test lamp does not illuminate and the circuit fuse is open
1. Ignition OFF, remove the test lamp and remove the fuse for the ignition voltage circuit.
2. Test for infinite resistance between the ignition voltage circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for greater than 2 ohms between the ignition voltage circuit terminal D and ground.
• If less than 2 ohms, repair the short to ground on the circuit.
• If greater than 2 ohms, test all the components connected to the circuit and repair or replace as necessary.
• If the test lamp illuminates
7. Ignition ON, test for 4.8-5.2 V between the mass air flow signal circuit terminal C and ground.
• If less than 4.8 V
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If greater than 5.2 V
Note: If the signal circuit is shorted to a voltage the engine control module or the sensor may be damaged.
1. Ignition OFF, disconnect the X1 harness connector at the K20 Engine Control Module.
2. Ignition ON, test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.
• If between 4.8-5.2 V
8. Ignition OFF, connect the leads of the EN 38522 - Variable Signal Generator as follows:
* Red lead to the signal circuit terminal C at the harness connector
* Black lead to ground
* Battery voltage supply lead to B+
9. Set the EN 38522 - Variable Signal Generator to the following specifications.
* Signal switch to 5 V
* Duty Cycle switch to 50 % (Normal)
* Frequency switch to 5 KHz
10. Engine idling.
11. Verify the scan tool MAF Sensor parameter is between 4,950-5,050 Hz.
• If not between 4,950-5,050 Hz.
Replace the K20 Engine Control Module.
• If between 4,950-5,050 Hz.
12. Test or replace the (5 Pin) B75B Mass Air Flow/Intake Air Temperature 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.
* Exhaust Gas Recirculation Valve Replacement Exhaust Gas Recirculation Valve Replacement
* Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (5 Pin) Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (5 Pin)Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (8 Pin) Mass Airflow Sensor with Intake Air Temperature Sensor Replacement (8 Pin) for (5 Pin) Mass Air Flow/Intake Air Temperature sensor replacement
* Control Module References Control Module References for ECM replacement, programming, and setup