anville Posted August 4, 2005 Report Share Posted August 4, 2005 I have a 96 Deville with a PC0101 code. I bought a used mass air flow sensor and installed it but nothing changed. I am looking for suggestions. Thank you. Link to comment Share on other sites More sharing options...
Ranger Posted August 5, 2005 Report Share Posted August 5, 2005 Maybe the used one was bad. Link to comment Share on other sites More sharing options...
KevinW Posted August 5, 2005 Report Share Posted August 5, 2005 Are there any other diagnostic codes reported? PC0101 (MAF sensor performance) can be triggered by factors not related directly to the sensor. The computer looks at the MAF signal and compares it to an internally calculated estimated airflow value (speed density); the code is set if there is too much of a discrepancy. The airflow estimate is based on variables like engine RPM, air inlet temperature, and manifold absolute pressure (MAP). Therefore, if one of these inputs is incorrect, the calculation will be affected. The diagnostic procedure in the service manual suggests to look for reasons that may affect these variables, like vacuum leaks (EGR, PCV, brake booster, MAP sensor feed, etc.), or indirectly via something that might admit more than the usual amount of air into the engine (missing or unseated oil dipstick or filler cap). ___________________________________________________ Link to comment Share on other sites More sharing options...
Logan Posted August 5, 2005 Report Share Posted August 5, 2005 This diagnostic test is used to determine if the Mass Air Flow sensor is providing proper readings to the PCM. The MAF sensor is a high frequency device that measures the rate of air flow through the throttle body. The MAF sensor outputs a series of pulses that vary in frequency with air flow. This signal is used by the PCM for fuel control. MAF readings during acceleration will be much higher than those during deceleration or idle. The PCM calculates what MAF reading should be received from the sensor under certain conditions. When the test conditions are met, the PCM will compare its calculated MAF value to the actual value received from the sensor. The calculated MAF reading is done by comparing MAP, RPM and Intake Air Temperature. The allowable difference between calculated MAF and actual MAF varies depending upon flow. If this difference is too great DTC P0101 will set. Conditions for Setting the DTC Test Conditions DTCs P0102, P0103, P0106, P0107, P0108, P0121, P0122, P0123, P0560 and P1108 not set. Ignition voltage between 11 volts and 16 volts DTC P0101 has not previously failed this ignition cycle. In closed loop fuel control. Canister Purge Duty Cycle is less than or equal to 99.6%. EGR rescaled pintle position is less than or equal to 240 counts. DTC P0401 not testing EGR. Traction control not active. TPS is less than or equal to 50 degrees. 100 msec delta MAP is less than or equal to 5 kPa. Failure Condition The difference between the actual and calculated MAF has been too great. Action Taken When the DTC Sets PCM turns ON the SERVICE EMISSION SYSTEM message. PCM disables the EVAP control solenoid. PCM disables long term fuel trim. PCM substitutes calculated MAF value, based on engine speed and throttle position, for actual MAF. PCM disables torque management. PCM maintains transaxle shift adapts at their current levels. PCM disables TCC. The PCM will illuminate the malfunction indicator lamp (MIL) when the diagnostic runs and fails. The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records. Conditions for Clearing the MIL/DTC The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail. A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test. Use a scan tool to clear DTCs. Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. Diagnostic Aids For an intermittently setting DTC P0101, compare the Freeze Frame data to the Typical Data list for the conditions under which the DTC set, looking for faulty data from other sensors which may set this DTC. Important An improperly installed air cleaner or a distorted /missing Intake Air Duct may cause this DTC to set. Ensure air cleaner assembly / IA duct is installed correctly and that there are no kinks, folds or damage to the IA Duct or possible debris in the air cleaner assembly or the MAF sensor inlet screen that may distort the air flow. Test Description Number(s) below refer to the step number(s) on the Diagnostic Table. Since calculated MAF is based on many inputs, these DTC's should be diagnosed first. If a miss or a rough running complaint is noted with or without DTC P0300, proceed to P0300 diagnosis first. Leaks downstream of the MAF sensor affect engine performance and actual MAF but won't be reflected in the calculated MAF sensor reading and may cause DTC P0101 to set. Logan Diagnostic LLC www.airbagcrash.com www.logandieselusa.com www.ledfix.com www.ledfix.com/yukontaillightrepair.html www.ledfix.com/ledreplacements.html www.ledfix.com/j42385toolrental.html Link to comment Share on other sites More sharing options...
spielberg911 Posted July 20, 2009 Report Share Posted July 20, 2009 This diagnostic test is used to determine if the Mass Air Flow sensor is providing proper readings to the PCM. The MAF sensor is a high frequency device that measures the rate of air flow through the throttle body. The MAF sensor outputs a series of pulses that vary in frequency with air flow. This signal is used by the PCM for fuel control. MAF readings during acceleration will be much higher than those during deceleration or idle. The PCM calculates what MAF reading should be received from the sensor under certain conditions. When the test conditions are met, the PCM will compare its calculated MAF value to the actual value received from the sensor. The calculated MAF reading is done by comparing MAP, RPM and Intake Air Temperature. The allowable difference between calculated MAF and actual MAF varies depending upon flow. If this difference is too great DTC P0101 will set. Conditions for Setting the DTC Test Conditions DTCs P0102, P0103, P0106, P0107, P0108, P0121, P0122, P0123, P0560 and P1108 not set. Ignition voltage between 11 volts and 16 volts DTC P0101 has not previously failed this ignition cycle. In closed loop fuel control. Canister Purge Duty Cycle is less than or equal to 99.6%. EGR rescaled pintle position is less than or equal to 240 counts. DTC P0401 not testing EGR. Traction control not active. TPS is less than or equal to 50 degrees. 100 msec delta MAP is less than or equal to 5 kPa. Failure Condition The difference between the actual and calculated MAF has been too great. Action Taken When the DTC Sets PCM turns ON the SERVICE EMISSION SYSTEM message. PCM disables the EVAP control solenoid. PCM disables long term fuel trim. PCM substitutes calculated MAF value, based on engine speed and throttle position, for actual MAF. PCM disables torque management. SERVICE EMISSIONS SYSTEM and PC0101 after I washed the car. I have cleaned the K&N Filter, Cleaned the MAF Sensor.Clear the code 20 times already but it keeps coming back.Sometimes I could drive up to 20 miles whithout any warnings & lights. Please Help PCM maintains transaxle shift adapts at their current levels. PCM disables TCC. The PCM will illuminate the malfunction indicator lamp (MIL) when the diagnostic runs and fails. The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records. Conditions for Clearing the MIL/DTC The PCM will turn the MIL OFF after three consecutive drive trips that the diagnostic runs and does not fail. A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail. A History DTC will clear after forty consecutive warm-up cycles with no failures of any emission related diagnostic test. Use a scan tool to clear DTCs. Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended. Refer to Clearing Diagnostic Trouble Codes in PCM Description and Operation. Diagnostic Aids For an intermittently setting DTC P0101, compare the Freeze Frame data to the Typical Data list for the conditions under which the DTC set, looking for faulty data from other sensors which may set this DTC. Important An improperly installed air cleaner or a distorted /missing Intake Air Duct may cause this DTC to set. Ensure air cleaner assembly / IA duct is installed correctly and that there are no kinks, folds or damage to the IA Duct or possible debris in the air cleaner assembly or the MAF sensor inlet screen that may distort the air flow. Test Description Number(s) below refer to the step number(s) on the Diagnostic Table. Since calculated MAF is based on many inputs, these DTC's should be diagnosed first. If a miss or a rough running complaint is noted with or without DTC P0300, proceed to P0300 diagnosis first. Leaks downstream of the MAF sensor affect engine performance and actual MAF but won't be reflected in the calculated MAF sensor reading and may cause DTC P0101 to set. Link to comment Share on other sites More sharing options...
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