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:

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. If KOER DTC P0505 is present, go to that diagnostic test. On A/T models, if vehicle cannot maintain an idle and engine stalls, go to step 3). If engine idles smoothly, increase engine speed to 1500 RPM for 5 seconds, then return to idle. Using scan tool, select MAF V PID from PID/DATA monitor menu. If PID value is less than .39 volt, go to next step. If PID value is .6-1.0 volt, go to step 9). For all other PID values, go to DTC P1101.

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 more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit. Reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Check Resistance Of VPWR Circuit

Turn ignition off. Leave MAF sensor disconnected. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between VPWR terminal of MAF sensor wiring harness connector and test pin No. 71 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.

Check MAF Circuit For Short To Ground Or MAF RTN Circuit

Disconnect scan tool from Data Link Connector (DLC). Measure resistance between test pin No. 88 (MAF SIG) and test pins No. 36 (MAF RTN), 51 and 103 (PWR GND) at breakout box. If all resistance readings are more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground and reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Check MAF RTN Circuit For Short To PWR GND Circuit

Measure resistance between test pin No. 36 (MAF RTN) and test pins No. 51 and 103 (PWR GND) at breakout box. If both resistance readings are more than 10,000 ohms, reconnect scan tool and go to next step. If resistance is 10,000 ohms or less, repair short to ground and reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Check Resistance Of MAF Signal Circuit

Measure resistance between MAF terminal at MAF sensor wiring harness connector and test pin No. 88 (MAF) 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 circuit and reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Check PWR GND Circuit To MAF Sensor

Connect PCM to breakout box. Turn ignition on. Measure voltage between VPWR and PWR GND terminals at MAF sensor wiring harness connector. If voltage is 10.5 volts or less, go to next step. If voltage is more than 10.5 volts, go to step 9).

Check PWR GND Circuit Resistance

Disconnect PCM from breakout box. Disconnect scan tool from Data Link Connector (DLC). Measure resistance between PWR GND terminal at 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 reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Check MAF RTN Circuit Resistance

Measure resistance between MAF RTN terminal at 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 reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Check MAF Circuit For Short To Ground In PCM

Connect PCM to breakout box. Disconnect scan tool from Data Link Connector (DLC). Measure resistance between test pin No. 88 (MAF) and test pins No. 36 (MAF RTN), 51 and 103 (PWR GND) at breakout box. If all resistance readings are more than 10 k/ohms, go to next step. If any resistance reading is 10 k/ohms or less, replace PCM.

Check MAF RTN Circuit For Short To Ground

Measure resistance between test pin No. 36 (MAF RTN) and test pins No. 51 and 103 (PWR GND) at breakout box. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, replace PCM.

Check MAF Circuit Output

Ensure ignition is off. Reconnect MAF sensor. Ensure PCM is connected 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) and negative battery terminal. If voltage is .34-1.96 volts, go to next step. If voltage is not .34-1.96 volts, replace MAF sensor and reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Measure Voltage Between MAF & MAF RTN Circuits

With engine idling, measure voltage between test pins No. 36 (MAF RTN) and No. 88 (MAF) at breakout box. If voltage is .34-1.96 volts, go to next step. If voltage is not .34-1.96 volts, replace MAF sensor and reset Keep-Alive Memory (KAM). To reset KAM, disconnect negative battery terminal for at least 5 minutes.

Check MAF Circuit Output With Scan Tool

Start engine and allow to idle. Using scan tool, select MAF V PID from PID/DATA monitor menu. If PID value is .34-1.96 volts, fault is intermittent and cannot be identified at this time. Go to DIAGNOSTIC TEST Z (INTERMITTENT) . If voltage is not .34-1.96 volts, replace PCM.