DTC P0102 Mass Air Flow Circuit Low Input (4JJ3 without DPD)

1. Engine control system check

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) Diagnostic system check-engine controls".

2. MAF sensor signal voltage check

1) Connect the scan tool.

2) Turn OFF the ignition switch for 1 minute or more.

3) Start the engine.

4) Observe the Mass Air Flow (MAF) Sensor parameter on the scan tool. Is the Mass Air Flow (MAF) Sensor parameter less than or equal to the specified value?

Value: 0.1 V

Yes

=>Go to Inspection for open circuit in MAF sensor power supply circuit.

No

Go to Intermittent conditions of engine.

Refer to "202.Engine 15D.Symptom(4JJ3 without DPD) intermittent conditions of engine".

3. Inspection for open circuit in MAF sensor power supply circuit

1) Turn OFF the ignition switch.

2) Disconnect the MAF and IAT sensor harness connector (C39).

3) Connect a test lamp between the ignition power supply circuit (pin 1 of C39) and the body ground.

Refer to "LHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

4) Turn ON the ignition switch. Does the test lamp illuminate?

Yes

=>Go to MAF sensor signal voltage check using fused jumper wire.

No

Repair the open circuit or high resistance in the ignition power supply circuit between the ENGINE 15A fuse and the MAF and IAT sensor (pin 1 of C39). Inspect the ENGINE 15A fuse first.

=>Go to Repair verification.

4. MAF sensor signal voltage check using fused jumper wire

1) Connect a fused jumper wire between the ignition power supply circuit and the signal circuit (pins 1 and 3 of C39).

Refer to "LHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

2) Observe the Mass Air Flow (MAF) Sensor parameter on the scan tool. Is the Mass Air Flow (MAF) Sensor parameter more than or equal to the specified value?

Value: 4.9 V

Yes

=>Go to MAF and IAT sensor harness connector inspection.

No

=>Go to Inspection for open circuit and short circuit in MAF sensor signal circuit.

5. Inspection for open circuit and short circuit in MAF sensor signal circuit

1) Inspect the MAF sensor signal circuit between the ECM (pin 28 of C10) and the MAF and IAT sensor (pin 3 of C39) for the following. Is the result normal?

  • Open circuit
  • Short to ground
  • Short to the low reference circuit
  • High resistance

Refer to "LHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM harness connector inspection.

No

Repair the circuit as necessary.

=>Go to Repair verification.

6. MAF and IAT sensor harness connector inspection

1) Inspect for poor connections at the MAF and IAT sensor harness connector (pins 1 and 3 of C39). Is the connection status normal?

Refer to "LHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

Replace the MAF and IAT sensor.

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) MAF and IAT sensor removal".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) MAF and IAT sensor installation".

=>Go to Repair verification.

No

Repair the connections as necessary.

=>Go to Repair verification.

7. ECM harness connector inspection

1) Inspect for poor connections at the ECM harness connector (pin 28 of C10). Is the connection status normal?

Refer to "LHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Engine Control (4JJ3 without DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to ECM replacement.

No

Repair the connections as necessary.

=>Go to Repair verification.

8. ECM replacement

Note

  • Perform programming after replacing the ECM.

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 without DPD) ECM setting".

Procedure completion

=>Go to Repair verification.

9. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 1 minute or more.

3) Start the engine.

4) Operate the vehicle under the conditions for running the DTC.

5) Observe the DTC information with a scan tool.