• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
---|---|---|---|---|---|
Ignition 1 Voltage | P0031, P0037, P0100, P0458 | P0100 | P0100 | -- | P0100 |
MAF Sensor Signal | P0100 | P0100 | P0100 | P0100 | P0101, P0102, P0103 |
Ground | -- | P0100 | P0100 | -- | P0100 |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Engine Running at various operating conditions Parameter Normal Range: 1,700-12,500 Hz | |||
Ignition 1 Voltage | 65,535 Hz | 65,535 Hz | -- |
MAF Sensor Signal | 65,535 Hz | 65,535 Hz | 65,535 Hz |
Ground | -- | 65,535 Hz | -- |
The mass air flow (MAF) sensor is integrated with the intake 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:
• | Ignition 1 voltage |
• | MAF sensor ground |
• | MAF sensor signal |
• | IAT sensor signal |
• | IAT low reference |
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 adaptation 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. |
• | DTCs P0010, P0011, P0013, P0014, P0096, P0097, P0098, P0099, P0100, P0102, P0103, P0106, P0107, P0108, P0121, P0122, P0123, P0221, P0222, P0223, P0236, P0237, P0238, P0335, P0336, P2088, P2089, P2090, P2091, P2176, P2227, P2228, or P2229 is not set. |
• | The engine is running. |
• | The engine coolant temperature (ECT) is warmer than 10°C (50°F). |
• | The ignition 1 voltage signal is greater than 10.5 volts. |
• | The change in the throttle position (TP) is less than 2 percent. |
• | The charge air bypass valve is closed. |
• | Long term cruise fuel trim needs to be active and stable. |
• | This DTC runs continuously within the enabling conditions. |
• | The ECM detects that the measured MAF is not within range of the calculated airflow based on throttle angle and engine speed. |
AND |
• | The ECM detects a significant error in the long term fuel trim at cruising speed. |
OR |
• | The ECM detects that the measured MAF is not within range of the calculated model that is derived from MAP. |
• | DTC P0101 is a Type B DTC. |
• | The ECM will disable boost control, and limit the system to mechanical boost only, resulting in a substantial decrease in engine power. |
DTC P0101 is a Type B DTC.
• | The charge air cooler (CAC) is connected to the turbocharger and to the throttle body by flexible ductwork 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 ductwork, the tightening specifications and proper positioning of the clamps is critical and must be strictly adhered to. |
• | Use a solution of dish soap and water in a spray bottle to pinpoint any suspected air leaks in the induction system and in the CAC assembly. |
• | A steady or intermittent high resistance of 15 ohms or greater on the ignition 1 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 impair 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. |
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 38522 Variable Signal Generator
• | Any damaged components |
• | Loose or improper installation |
• | An air flow restriction |
• | Vacuum leaks |
• | A turbocharged air leak |
• | Improperly routed vacuum hoses |
• | In cold climates, inspect for any snow or ice buildup |
• | Inspect the MAF sensor elements for contamination |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. |
⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
⇒ | If the MAF Sensor parameter is not within the specified range, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for ECM replacement, setup, and programming |