DTC P0171 Or DTC P0172: Condition

DTC P0171 is set when ECM (PCM) detects that total fuel trim of bank No. 1 is more than 33 percent. DTC P0172 is set when ECM (PCM) detects that total fuel trim of bank No. 1 is less than -33 percent. MIL is illuminated when ECM (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are:

• Intake system vacuum leaks.
• Exhaust system leaks.
• Incorrect fuel pressure.
• Fuel injector malfunction.
• HO2S Bank 1, Sensor 1 malfunction.
• Mass Air Flow (MAF) sensor malfunction.
• Engine Coolant Temperature (ECT) sensor malfunction.
• Fuel level sensor malfunction.