Diagnostic Trouble Codes Troubleshooting

DTC TROUBLESHOOTING

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	Is there DTC(s) other than "P0171" and "P0172"?	Go to applicable DTC flow.	Go To Step 3.
3	Check intake system and exhaust system for leakage Are intake system and exhaust system in good condition?	Go To Step 4.	Repair or replace.
4	Check fuel pressure Check fuel pressure referring to "FUEL PRESSURE CHECK :". Is check result satisfactory?	Go To Step 5.	Repair or replace.
5	Check fuel injectors Check fuel injectors referring to FUEL INJECTOR INSPECTION . Is check result satisfactory?	Go To Step 6.	Faulty injector(s) or its circuit.
6	Check fuel level sensor Check fuel level sensor referring to Step 2 of DTC P0461: FUEL LEVEL SENSOR CIRCUIT RANGE / PERFORMANCE PROBLEM . Is check result satisfactory?	Go To Step 7.	Faulty fuel level sensor or its circuit.
7	Check MAF sensor Check MAF sensor referring to Step 2 and 3 of "DTC P0101: MASS AIR FLOW CIRCUIT RANGE / PERFORMANCE PROBLEM :". Is check result satisfactory?	Go To Step 8.	Faulty MAF sensor or its circuit.
8	Check ECT sensor Check ECT sensor referring to Step 4 and 5 of "DTC P0116: ENGINE COOLANT TEMPERATURE CIRCUIT RANGE / PERFORMANCE :". Is check result satisfactory?	Go To Step 9.	Faulty ECT sensor or its circuit.
9	Check HO2S-1 Check HO2S-1 referring to Step 2 of "DTC P0131 / P0132: 02 SENSOR CIRCUIT LOW / HIGH VOLTAGE (SENSOR-1) :". Is check result satisfactory?	Substitute a known-good ECM and recheck.	Faulty HO2S-1 or its circuit.