DTC Troubleshooting

Control System DTCs

DTC Troubleshooting: P0102

DTC P0102 : MAF Sensor Circuit Low Voltage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information How To Troubleshoot The Fuel And Emissions Systems.

1. Problem verification:

Problem verification
-1. Turn the ignition switch to ON (II), and wait 2 seconds.

-2. Check the MAF SENSOR in the DATA LIST with the HDS.

Is about 0 g/s, or 0.1 V or less indicated?
-YES- The failure is duplicated. Go to step 2.
-NO- Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the MAF sensor/IAT sensor and the ECM/PCM.

2. Shorted wire check (IG1_ACG, IG1(AFM) lines)

Shorted wire check (IG1_ACG, IG1(AFM) lines)
-1. Turn the ignition switch to LOCK (0).

-2. Check the following fuse.





Is the fuse OK?
-YES- The IG1_ACG/IG1(AFM) wires are not shorted. Go to step 3.
-NO- Repair a short in the IG1_ACG/IG1(AFM) wire between the MAF sensor/IAT sensor and the No. B2 (15 A) fuse. Also replace the No. B2 (15 A) fuse, then do the repair verification.

3. Open wire check (IG1(AFM) line):

Open wire check (IG1(AFM) line)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connector.





-3. Turn the ignition switch to ON (II).

-4. Measure the voltage between test points 1 and 2.









Is there battery voltage?
-YES- The IG1(AFM) wire is OK. Go to step 4.
-NO- Repair an open in the IG1(AFM) wire between the No. B2 (15 A) fuse and the MAF sensor/IAT sensor, then do the repair verification.

4. Determine possible failure area (VGP line, others):

Determine possible failure area (VGP line, others)
-1. Turn the ignition switch to LOCK (0).

-2. Measure the resistance between test points 1 and 2.









Is there 190-210 kOhms?
-YES- Go to step 7.
-NO- Go to step 5.

5. Shorted wire check (VGP line):

Shorted wire check (VGP line)
-1. Jump the SCS line with the HDS

-2. Disconnect the following connector.





-3. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- Repair a short in the VGP wire between the ECM/PCM (B22) and the MAF sensor/IAT sensor, then do the repair verification.
-NO- The VGP wire is not shorted. Go to step 6.

6. Open wire check (VGP line):

Open wire check (VGP line)
-1. Check for continuity between test points 1 and 2.









Is there continuity?
-YES- The VGP wire is OK. Update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM Service and Repair, then do the repair verification.
-NO- Repair an open in the VGP wire between the ECM/PCM (B22) and the MAF sensor/IAT sensor, then do the repair verification.

7. MAF sensor/IAT sensor check (substitution):

MAF sensor/IAT sensor check (substitution)
-1. Substitute a known-good MAF sensor/IAT sensor. Service and Repair

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Clear the DTC with the HDS.

-5. Start the engine. Hold the engine speed at 2,000 rpm without load (A/T in P or N, M/T in neutral).

-6. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0102 indicated?
-YES- The MAF sensor/IAT sensor is OK. Update the ECM/PCM ECM/PCM Update if it does not have the latest software, or substitute a known-good ECM/PCM Service and Repair, then do the repair verification.
-NO- Replace the original MAF sensor/IAT sensor Service and Repair, then do the repair verification.

Repair verification:

-1. Turn the ignition switch to LOCK (0).

-2. Reconnect all connectors.

-3. Turn the ignition switch to ON (II).

-4. Reset the ECM/PCM with the HDS. How To Troubleshoot The Fuel And Emissions Systems

-5. Do the ECM/PCM idle learn procedure. ECM/PCM Idle Learn Procedure

-6. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0102 indicated?
-YES- Check for poor connections or loose terminals at the MAF sensor/IAT sensor and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM Service and Repair, then recheck. If the ECM/PCM was substituted, go to step 1.
-NO- Troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.