P0171

NOTE: This DTC requires two "trips" or two driving cycles unless the SCS service connector is connected.

P0171 - The scan tool indicates Diagnostic Trouble Code (DTC) P0171 - The fuel system is too lean [Right Bank (Bank 1)].

Description
By monitoring the Long Term Fuel Trim, long term malfunctions in the fuel system will be detected.

If a malfunction has been detected during two consecutive trips, the MIL will come on and DTC P0171 will be stored.

NOTE: If some of the DTCs listed below are stored at the same time as DTC P0171, troubleshoot those DTCs first, then troubleshoot DTC P0171.

P0107, P0108, P1128, P1129 - MAP Sensor
P0135 - Right Primary HO2S Heater (Bank 1, Sensor 1)
P0137, P0138 - Secondary HO2S (Sensor 2)
P0141 - Secondary HO2S Heater (Sensor 2)
P0155 - Left Primary HO2S Heater (Bank 2, Sensor 1)
P0401 - EGR Flow Insufficient
P1491 - EGR Valve Lift Insufficient
P1498 - EGR Valve Position Sensor High Voltage

Possible Cause

DTC P0171, P0174 System Too Lean
- Fuel Pump insufficient flow/pressure
- Fuel Feed Line clogged, leaking
- Fuel Pressure Regulator stuck open
- Fuel Filter clogged
- Injector clogged, air inclusion
- Gasoline doesn't meet Owner's Manual spec.
- Primary HO2S (Sensor 1) deteriorated
- EGR System insufficient flow
- Exhaust leak

Troubleshooting Flowchart: