DTC P0101 Mass Air Flow Circuit Range/Performance (4JJ3 with DPD)

Note

When the intake air that is not measured flows from the MAF sensor to the engine, this DTC is set.
The MAF sensor detects lower than normal value if the MAF sensor signal circuit is shorted to the IAT sensor signal circuit when the air flow rate is high.
The Mass Air Flow (MAF) Sensor parameter on the scan tool is updated only once while the engine is running, or after the key is turned when 10 seconds or more have passed with the ignition switch OFF.

1. Engine control system check

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) Diagnostic system check-engine controls".

2. Air intake/exhaust system inspection

1) Inspect for the following. Is the result normal?

Clogged air cleaner element, collapsing of the air intake piping between the air cleaner and inlet manifold, or a state where flow is restricted or breakage is present
Leakage in the air intake system
Dirt or foreign material blocking the inlet of the MAF sensor
Misdetection or delayed response of the MAF sensor
Water in the air intake system
Conditions that restrict exhaust system flow
Stuck intake throttle valve
Stuck EGR valve
Stuck VGS actuator

Yes

=>Go to Individual harness connector inspection.

Repair or replace as necessary.

=>Go to Repair verification.

3. Individual harness connector inspection

1) Inspect for poor connections at the MAF and IAT sensor harness connector (pins 1, 2, and 3 of C39). Is the connection status normal?

2) Inspect for poor connections at the ECM harness connector (pin 24 of C9, and pins 19 and 28 of C10). Is the connection status normal?

Refer to "RHD Engine Control (4JJ3 with DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (4JJ3 with DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

3) Are all of the results normal?

Yes

=>Go to Inspection for high resistance in MAF sensor circuit.

Repair the connections as necessary.

=>Go to Repair verification.

4. Inspection for high resistance in MAF sensor circuit

1) Inspect the MAF sensor circuit between the ECM (pin 24 of C9 and pin 28 of C10) and the MAF and IAT sensor (pins 2 and 3 of C39) for high resistance. Is the result normal?

Refer to "RHD Engine Control (4JJ3 with DPD)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (4JJ3 with 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 with DPD) MAF and IAT sensor removal".

Refer to "1.Engine 1Z.Engine Electrical Control(4JJ3 with DPD) MAF and IAT sensor installation".

=>Go to Repair verification.

Repair the circuit as necessary.

=>Go to Repair verification.

5. 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.