Diagnostic Test - MAF Sensor (Sent) Faults

TECH TIPS: 

• The MAF Single Edge Nibble Transmission (SENT) sensor is a one-way, asynchronous sensor which only requires three wires to operate, 5V supply, signal, and ground. This sensor provides digital readings of the Intake Air Temperature (IAT), Turbocharger Inlet Pressure (TIP), and Mass Air Flow (MAF) to the PCM. During normal operation, the SENT sensor is powered up and the internal transceiver automatically starts transmitting data to the PCM.
• Refer to the PCM VERIFICATION Test information at the bottom of the test procedure to determine any routines or procedures that must be performed for the system to operate correctly after repairs are made. 

MAF/IAT/TIP SENSOR CIRCUIT FAULT DIAGNOSTICS (P0F51, P0100, P0110, P012A): 

The PCM receives a signal from the MAF sensor that the voltage for one of the internal sensors is too high or too low due to an internal sensor issue.

1. Replace the MAF sensor in accordance with the service information.

MAF SENSOR PERFORMANCE FAULT DIAGNOSTIC (P0111, P012B): 

The PCM detects that either the internal intake air temperature feedback or turbocharger inlet pressure feedback is out of range when compared to other similar engine sensors due to an internal MAF sensor issue.

1. Replace the MAF sensor in accordance with the service information.

MAF SENSOR PERFORMANCE FAULT DIAGNOSTIC (P0101): 

The PCM detects that when the DTC set, the engine was running, MAF sensor feedback was valid, and there are no throttle feedback errors. The vehicle is likely running rough with the possibility of an audible boost leak, and the MIL light is on.

1. Visually inspect for any of the following issues and repair as necessary:
   1. Engine mechanical issue.
   2. Vacuum leaks.
   3. Air inlet system leaks or plugged.
   4. If there are no problems with any of the listed issues or an audible boost leak then continue to step 2  .
2. Replace the MAF sensor in accordance with the service information.

MAF SENSOR COMMUNICATION FAULT DIAGNOSTICS (U060F, U0611, U068B): 

The PCM detects that the MAF sensor is no longer sending feedback data (air flow/temp/pressure) over the signal wire. When only a single communication DTC sets then this would indicate that the fault is within the sensor. However, if all three communication DTCs are reporting then the sensor wiring needs investigating for an open, short to ground, or short to battery in the MAF sensor supply circuit.

1. How many of the MAF sensor communication DTCs are set?
   1. If only one communication DTC is set, replace the MAF sensor in accordance with the service information.
   2. If all three communication DTCs are set, continue to step 2  .
2. Turn the ignition off. Check the MAF sensor harness connector for a proper connection at the sensor. Verify that the connector is completely plugged in and properly locked prior to disconnecting for testing. Disconnect the sensor harness connector and check for any pushed out, damaged, corroded discolored or spread terminals causing intermittent or non contact.
   1. If any damage is found to the connector or terminals, repair the connector or terminals, clear the DTCs and retest. If the communication DTC returns, continue to step 3  .
   2. If the connector and terminals appear in good shape, continue to step 3  .
3. Turn the ignition on and measure the voltage on the 5V supply circuit. The voltage should read approximately 5.0 volts or higher.
   1. If there is no voltage present on the 5V supply circuit, repair the 5V supply circuit for an open or short to ground.
   2. If voltage is present on the 5V supply circuit, continue to step 4 
4. Turn the ignition off. Disconnect the PCM harness connector. Check for continuity between ground and the MAF sensor signal circuit at the MAF sensor harness connector. There should be no continuity between ground and the signal circuit.
   1. If the there is no continuity between ground and the sensor signal, continue to step 5 
   2. If there is continuity between ground and the sensor signal circuit, repair the sensor signal circuit for a short to ground.
5. Measure the resistance of the sensor signal circuit between the MAF sensor harness connector and the PCM harness connector. Typically, the resistance should be less than 5.0 Ohms.
   1. If the resistance is below 5.0 Ohms, continue to step 6 
   2. If the resistance is above 5.0 Ohms, repair the sensor signal circuit for an open or high resistance,
6. Turn the ignition off. Disconnect the PCM harness connector. Measure the resistance of the sensor ground circuit between the MAF sensor harness connector and the PCM harness connector. Typically, the resistance should be less than 5.0 Ohms.
   1. If the resistance is below 5.0 Ohms, continue to step 7 
   2. If the resistance is above 5.0 Ohms, repair the sensor ground circuit for an open or high resistance,
7. Replace the MAF sensor and retest for DTCs.
   1. If the DTC does not return, replacing the sensor repaired the fault.
   2. If the DTC does return, replace the Powertrain Control Module in accordance with the service information.