DTC P0112 (Flash Code 22) Intake Air Temperature Sensor Circuit Low (RZ4E-TC)

1. Engine control system check

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Diagnostic system check-engine controls".

2. IAT sensor signal voltage check

1) Observe the Intake Air Temperature (IAT) Sensor parameter on the scan tool. Is the Intake Air Temperature (IAT) Sensor parameter less than or equal to the specified value?

Value: 0.1 V

Yes

=>Go to IAT sensor signal output voltage check.

No

Go to Intermittent conditions of engine.

Refer to "202.Engine 15D.Symptom(RZ4E-TC) intermittent conditions of engine".

3. IAT sensor signal output voltage check

1) Turn OFF the ignition switch.

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

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

3) Turn ON the ignition switch.

4) Observe the Intake Air Temperature (IAT) Sensor parameter on the scan tool. Is the Intake Air Temperature (IAT) Sensor parameter more than or equal to the specified value?

Value: 4.5 V

Yes

Replace the MAF and IAT sensor.

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) MAF and IAT sensor removal".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) MAF and IAT sensor installation".

=>Go to Repair verification.

No

=>Go to Inspection for short to ground in IAT sensor signal circuit.

4. Inspection for short to ground in IAT sensor signal circuit

1) Inspect the IAT sensor signal circuit between the ECM (pin 72 of C7) and the MAF and IAT sensor (pin 4 of C39) for the following. Is the result normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" 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.

5. ECM harness connector inspection

1) Inspect for poor connections at the ECM harness connector (pins 60 and 72 of C7). Is the connection status normal?

Refer to "RHD Engine Control (RZ4E)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "LHD Engine Control (RZ4E)" 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.

6. ECM replacement

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM removal".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM installation".

Refer to "1.Engine 1Z.Engine Electrical Control(RZ4E-TC) ECM setting".

Procedure completion

=>Go to Repair verification.

7. Repair verification

1) Clear the DTC with a scan tool.

2) Turn OFF the ignition switch for 30 seconds 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.