Okay,
101 is for the mass air flow. Check the connector at the mass air flow for any damaged or burned pins.
171,174 is a vacuum leak or running lean.
The 420 is a bad catalytic converter. The precious metals are worn out internally.
Roy
P0101
Item Description
Symptom/DTC P0101
Descriptor
With Tac
Probable Causes
Aftermarket Accessories
Air Filter Element Deteriorating
Air Induction System Water Intrusion
Exhaust System Restriction
Manifold Absolute Pressure (MAP) Sensor Skewed
Mass Airflow (MAF) Sensor Contamination
Mass Airflow (MAF) Sensor Harness Routing
Mass Airflow (MAF) Sensor/Intake Air Temperature (IAT) Sensor
Mass Airflow (MAF)/Intake Air Temperature (IAT) Sensor Debris
Vacuum Leak
Wide Open Throttle (WOT) From a Stop
P0171
Item Description
Symptom/DTC P0171
Descriptor
Probable Causes
Air Intake Duct Leaks
Air Shut-off Valves Not Closing
Air System Leaks
Crankcase Ventilation System Leaks
Fuel Contamination - Alcohol
Insufficient Fuel in Tank
Leaking Exhaust Gas
Other DTCs
Vacuum Hose Damage, Improper Connection
Vacuum Leak
P0420
Item Description
Symptom/DTC P0420
Descriptor
Probable Causes
Engine Misfire
Exhaust Leak
Fuel Contamination, Fuel Additive
Heated Oxygen (HO2S) Sensor 2 Road Damage
High Engine Oil and or Coolant Consumption
Oxygen Sensor (O2) bank 1
Rich and or lean Fuel Mixture
Spark Timing Retarded
Three Way Converter (TWC) Physical Damage
Three Way Converter (TWC) Restricted Exhaust
Three Way Converter (TWC) does not Meet Original Equipment Manufacturer (OEM) Specifications
Weak or Poor Spark
Tuesday, May 1st, 2018 AT 3:37 AM
