suspect O2 sensor
(A/F sensor )
DTC P0171 is set when fuel trim is driven rich beyond a certain value with engine at normal operating temperature and the actual air/fuel ratio is lean. Possible causes are:
Air induction system malfunction.
Fuel injector restricted.
Defective Mass Airflow (MAF) meter.
Defective Engine Coolant Temperature (ECT) sensor.
Ignition system malfunction.
Improper fuel pressure.
Exhaust system leak.
Air/Fuel (A/F) sensor circuit is open or shorted.
Defective A/F sensor.
Defective ECM.
Vehicle ran out of fuel
p0125
Heated Air/Fuel (A/F) sensor monitors exhaust gas oxygen content and delivers input signals to ECM. Heated A/F sensor is located on exhaust pipe in front of catalytic converter. A/F sensor may also be referred to as A/F sensor (bank No. 1 sensor No. 1) or A/F ratio sensor. ECM uses input signals to determine fuel injection system operation. DTC is set when A/F sensor output voltage does not change after engine is started with engine at normal operating temperature, engine speed of 1500 RPM or more and with vehicle speed of 25-62 MPH for at least 1.5 minutes. Possible causes are:
A/F sensor circuit is open or shorted.
Defective A/F sensor.
Air induction system malfunction.
Improper fuel pressure.
Defective fuel injector.
Exhaust system leak.
Vehicle has run out of fuel.
Defective ECM.
p1130
Heated Air/Fuel (A/F) sensor monitors exhaust gas oxygen content and delivers input signals to ECM. Heated A/F sensor is located on exhaust pipe in front of catalytic converter. A/F sensor may also be referred to as A/F sensor (bank No. 1 sensor No. 1) or A/F ratio sensor. ECM uses input signals to determine fuel injection system operation. DTC is set when A/F sensor output voltage does not change after engine is started with engine at normal operating temperature. Possible causes are:
A/F sensor circuit is open or shorted.
Defective A/F sensor.
Air induction system malfunction.
Improper fuel pressure.
Defective fuel injector.
Vehicle has run out of fuel.
Defective ECM.
p1135
Heated Air/Fuel (A/F) sensor monitors exhaust gas oxygen content and delivers input signals to ECM. Heated A/F sensor is located on exhaust pipe in front of catalytic converter. A/F sensor may also be referred to as A/F sensor (bank No. 1 sensor No. 1) or A/F ratio sensor. ECM uses input signals to determine fuel injection system operation. DTC is set when A/F sensor heater current draw exceeds 8 amps or is .25 amp or less when heater operates. Possible causes are:
A/F sensor circuit is open or shorted.
Defective A/F sensor.
Defective ECM.
May 5, 2009 at 7:26 PM
