P0171

DTC P0171 / P0172

DTC Detecting Condition and Trouble Area






Circuit Diagram










DTC Confirmation Procedure

WARNING:

If you do not select a suitable route and take proper precautions when performing a road test, an accident can occur.

- Select a level road with no traffic to minimize the risk of accident.
- Perform the test extremely carefully.
- Perform the road test using 2 persons, a driver and an assistant.

NOTE:

- Be sure to troubleshoot first unexpected DTCs previously detected in "DTC Confirmation Procedure".
- Confirm that the following conditions are met in this "DTC Confirmation Procedure".

- BARO > 75 kPa (0.8 kgf/cm2, 10.8 psi, 0.75 bar)

- DTC P0102, P0103, P0131, P0132 or P2237 is not detected.

1) Warm up engine to normal operating temperature.
2) Drive vehicle at 50 - 60 km/h (31 - 37 mile/h) for 3 min. (Keep throttle valve opening constantly in this step.)

DTC Troubleshooting

1.
Was "Engine and Emission Control System Check" performed?
YES -
Go to Step 2.
NO -
Go to Engine and Emission Control System Check Engine and Emission Control System Check.

2. DTC check

Check DTC.

Is there DTC(s) other than P0171 and P0172?
YES -
Go to troubleshooting for applicable DTC(s).
NO -
Go to Step 3.

3. Exhaust system and air intake system check

Check exhaust system and air intake system for clogging or leak.

Are they in good condition?
YES -
Go to Step 4.
NO -
Repair or replace defective parts.

4. Fuel system check

Check fuel system. Fuel System Inspection

Is it in good condition?
YES -
Go to Step 5.
NO -
Repair or replace defective parts or wire harness.

5. MAF sensor performance check

Confirm that ignition mode of keyless push start system is in "OFF".
Connect scan tool to DLC.
Warm up engine to normal operating temperature.
Check MAF value using scan tool. (Refer to Scan Tool Testing and Procedures Scan Tool Data
for normal value.)

Is normal value indicated?
YES -
Go to Step 6.
NO -
Repair or replace defective parts or wire harness.

6. ECT sensor circuit check

Check "A1" and "A2" circuits according to Step 3 of P0116 DTC P0116 / P0125 / P0128.

Are they in good condition?
YES -
Go to Step 7.
NO -
Repair or replace defective wire harness.

7. ECT sensor check

Check ECT sensor. ECT Sensor Inspection

Is it in good condition?
YES -
Go to Step 8.
NO -
Replace ECT sensor. ECT Sensor Removal and Installation

8. DTC recheck

Replace A/F sensor. Service and Repair
Perform DTC confirmation procedure and check DTC.

Is DTC P0171 or P0172 still detected?
YES -
Replace ECM and recheck DTC. Service and Repair
NO -
End.