Honda CR-V 1997 Service Manual page 326

PGM-FI System
Fuel Supply System
I
P0171
I
The scan tool indicates Diagnostic Trouble Code (DTC) P0171: The fuel system is too lean.
I
P0172
I
The scan tool indicates Diagnostic Trouble Code (DTC) P0172: The fuel system is too rich.
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 andlor POl72 will be
stored.
NOTE: If some of the DTCs listed below are stored at the same time as DTC P0171
andlor
POl72, troubleshoot those DTCs
first, then troubleshoot DTC P0171
andlor
POl72.
P0107, P0108, Pl128, Pl129: MAP Sensor
P0135: Primary H02S (Sensor 1) Heater
P0137, P0138: Secondary H02S (Sensor 2)
P0141: Secondary H02S (Sensor 2) Heater
P0441": EVAP System Insufficient Purge Flow
P1456", P1457": EVAP System Insufficient Purge Flow *1: '97 model
Possible Cause
DTC P0171
S
stem too
lean
DTC POl72
5 stem too rich
11-124
*2: '98 - 00 models
Fuel Pump insufficient flow/pressure
Fuel Feed Line clogged, leaking
Fuel Pressure Regulator stuck open
Fuel Filter clogged
Fuel Injector clogged, air leakage
Gasoline doesn't meet Owner's Manual spec.
Primary H02S (Sensor 1) deteriorated
Valve Clearance
Exhaust leak
Fuel Pressure Regulator clogged. stuck closed
Fuel Return Pipe clogged
Fuel Injector
leaking
Gasoline doesn't meet Owner's Manual spec.
Primary H02S (Sensor 1) deteriorated
EVAP Purge Control Solenoid Valve leaking, stuck opened
Valve Clearance