DTC Troubleshooting

DIAGNOSTIC PROCEDURES CHART

Step	Action	YES	NO
1	Was "Engine and Emission Control System Check" performed?	Go to Step 2.	Go to ENGINE AND EMISSION CONTROL SYSTEM CHECK .
2	DTC check Check DTC. Is there DTC(s) other than P0171 and P0172?	Go to troubleshooting for applicable DTC(s).	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?	Go to Step 4.	Repair or replace defective parts.
4	Fuel system check Check fuel system, see FUEL SYSTEM INSPECTION . Is it in good condition?	Go to Step 5.	Repair or replace defective parts or wire harness.
5	MAF sensor performance check Confirm that ignition mode of keyless push start system is "OFF". Connect scan tool to DLC. Warm up engine to normal operating temperature. Check MAF value using scan tool. (Refer to SCAN TOOL DATA for normal value.) Is normal value indicated?	Go to Step 6.	Repair or replace defective parts or wire harness.
6	ECT sensor circuit check Check "A1" and "A2" circuits according to Step 3 of DTC P0116/P0125/P0128 . Are they in good condition?	Go to Step 7.	Repair or replace defective wire harness.
7	ECT sensor check Check ECT sensor, see ECT SENSOR INSPECTION . Is it in good condition?	Go to Step 8.	Replace ECT sensor, see ECT SENSOR REMOVAL AND INSTALLATION .
8	DTC recheck Replace A/F sensor, see A/F SENSOR AND HO2S REMOVAL AND INSTALLATION . Perform DTC confirmation procedure and check DTC. Is DTC P0171 or P0172 still detected?	Replace ECM and recheck DTC, see ECM REMOVAL AND INSTALLATION .	End.