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DTC P0102 - Mass Airflow (MAF) Sensor: Condition

DTC P0102 indicates MAF signal was less than 0.39 volt sometime during normal engine operation. Possible causes for this fault are:

1) Check MAF Low Input Signal To PCM  Ensure air induction system is okay. Repair if necessary. Start engine and allow to idle. If engine does not idle smoothly, repair cause of rough idle condition before continuing. With scan tool connected, raise engine speed to 1500 RPM and return to idle. Access MAF PID. If MAF PID is less than 0.39 volt, go to next step. If MAF PID is 0.6-1.0 volt, go to step 10). For all other MAF PID readings, go to step 13).

2) Check VPWR Circuit Voltage  Turn ignition off. Disconnect MAF sensor. Turn ignition on. Measure voltage between VPWR terminal of MAF sensor wiring harness connector and negative battery terminal. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open in VPWR circuit.

3) Check Resistance Of VPWR Circuit  Turn ignition off. Leave MAF sensor disconnected. Disconnect PCM 104-pin connector and inspect for damage. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between VPWR terminal of MAF sensor wiring harness connector and test pins No. 71 and 97 (VPWR) at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in VPWR circuit and repeat QUICK TEST.

4) Check MAF Circuit For Short To Ground & MAF RTN Circuit  Leave ignition off and MAF disconnected. Ensure PCM is disconnected. Disconnect scan tool from DLC (if applicable). Measure resistance between test pin No. 88 (MAF SIG) and test pins No. 36 (MAF RTN), 24 and 103 (PWR GND) at breakout box. If resistance is 10,000 ohms or more, reconnect scan tool and go to next step. If resistance is less than 10,000 ohms, repair circuit short to ground and repeat QUICK TEST.

5) Check Resistance Of MAF SIG Circuit  Leave ignition off, PCM and MAF disconnected. Measure resistance between MAF terminal of MAF sensor wiring harness connector and test pin No. 88 (MAF SIG) at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open circuit in MAF SIG circuit and repeat QUICK TEST.

6) Check PWR GND Circuit To MAF Sensor  Leave ignition off and MAF disconnected. Connect PCM to breakout box. Turn ignition on. Measure voltage between VPWR and PWR GND terminal of MAF sensor wiring harness connector. If voltage is less than 10.5 volts, go to next step. If voltage is 10.5 volts or more, go to step 14).

7) Check PWR GND Circuit Resistance  Leave ignition off and MAF sensor disconnected. Disconnect PCM from breakout box. Disconnect scan tool from DLC (if applicable). Measure resistance between PWR GND terminal of MAF sensor wiring harness connector and negative battery terminal. If resistance is less than 10 ohms, go to next step. If resistance is 10 ohms or more, repair open in PWR GND circuit and repeat QUICK TEST.

8) Check MAF RTN Circuit Resistance  Leave ignition off and PCM and MAF sensor disconnected. Measure resistance between MAF RTN terminal of MAF sensor wiring harness connector and test pin No. 36 (MAF RTN) at breakout box. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in MAF RTN and repeat QUICK TEST.

9) Check MAF Circuit For Short To Ground In PCM  Leave ignition off and MAF disconnected. Connect PCM to breakout box. Disconnect scan tool from DLC (if applicable). Measure resistance between test pin No. 88 (MAF SIG) and test pins No. 36 (MAF RTN), 24 and 103 (PWR GND) at breakout box. If resistance is 10,000 ohms or more, go to next step. If resistance is less than 10,000 ohms, replace PCM and repeat QUICK TEST.

10) Check MAF Circuit Output  Ensure ignition is off. Reconnect MAF sensor. Connect PCM to breakout box. Start engine and allow to idle. If engine does not idle smoothly, repair cause of rough idle condition before continuing. Measure voltage between test pin No. 88 (MAF SIG) and negative battery cable. If voltage is 0.34-1.96 volts, go to next step. If voltage is not 0.34-1.96 volts, replace MAF sensor and repeat QUICK TEST.

11) Verify MAF Circuit Input & Output  Ensure ignition is off and MAF sensor and PCM are connected. With engine idling, measure voltage between test pins No. 36 (MAF RTN) and 88 (MAF SIG). If voltage is 0.34-1.96 volts, go to next step. If voltage is not 0.34-1.96 volts, replace MAF sensor and repeat QUICK TEST.

12) Check MAF Circuit Output With Scan Tool  Start engine and allow to idle. Access MAF PID on scan tool. If PID voltage is 0.34-1.96 volts, fault is intermittent and cannot be identified at this time. Go to CIRCUIT TEST Z (INTERMITTENT). If voltage is not 0.34-1.96 volts, replace PCM and repeat QUICK TEST.

NOTE: DTC P1101 may be caused by low battery charge or by use of a garage exhaust ventilation system. Ensure vehicle is vented to outside atmosphere before repeating QUICK TEST.

13) Check MAF Sensor Output Voltage  Turn ignition off. Ensure MAF sensor is connected. Disconnect PCM 104-pin connector and inspect for damage. Repair as necessary. Install Breakout Box (014-00950). Leave PCM connected to breakout box. With scan tool connected, turn ignition on. Measure voltage between test pin No. 88 (MAF SIG) and test pins No. 24 and 103 (PWR GND). If voltage is greater than 0.2 volt, go to step 7). If voltage is 0.2 volt or less, go to step 3).

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