DTC Troubleshooting

DTC TROUBLESHOOTING 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	Is there DTC (s) other than "DTC P0171 / P0174"?	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 referring to "FUEL PRESSURE CONTROL SYSTEM INSPECTION ". Is check result satisfactory?	Go to Step 5.	Repair or replace.
5	Check fuel injectors referring to "FUEL INJECTOR INSPECTION ". Is check result satisfactory?	Go to Step 6.	Faulty injector(s).
6	Check fuel level sensor referring to "DTC P0461: FUEL LEVEL SENSOR CIRCUIT PERFORMANCE ". Is check result satisfactory?	Go to Step 7.	Faulty fuel level sensor or its circuit.
7	Check MAF sensor for performance referring to "DTC P0101: MASS AIR FLOW CIRCUIT PERFORMANCE ". Is check result satisfactory?	Go to Step 8.	Faulty MAF sensor or its circuit.
8	Check ECT sensor referring to "ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION ". Is check result satisfactory?	Go to Step 9.	Faulty ECT sensor.
9	Check HO2S-1 referring to "DTC P0131 / P0132 / P1131 / P1132: O2 SENSOR (BANK 1 SENSOR -1) CIRCUIT LOW VOLTAGE SHIFT / HIGH VOLTAGE SHIFT / CIRCUIT CONTINUITY / CIRCUIT HIGH VOLTAGE " or "DTC P0151 / P0152 / P1151 / P1152: O2 SENSOR (BANK 2 SENSOR-1) CIRCUIT LOW VOLTAGE SHIFT / HIGH VOLTAGE SHIFT / CIRCUIT CONTINUITY / CIRCUIT HIGH VOLTAGE ". Is check result satisfactory?	Substitute a known-good ECM and recheck.	Faulty HO2S-1.