P0172 System Too Rich (Bank - Subaru Impreza 2005 General Description Manual

Diagnostic Trouble Code (DTC) Detecting Criteria
AF:DTC P0172 SYSTEM TOO RICH (BANK 1)
1. OUTLINE OF DIAGNOSIS
Detect the fuel system malfunction by the amount of main feedback control.
• Fuel System Diagnosis
(1)
(1) Purge control solenoid valve
(2) Purge valve
(3) Pressure regulator
(4) Throttle body
(5) Fuel filter
(6) Intake manifold
(7) Engine control module (ECM)
(8) Canister
(9) Pressure control solenoid valve
(10) Drain valve
(11) Drain filter
(12) Shut-off valve
(13) Vent valve
• Diagnostic Method
Fuel system is diagnosed by comparing the target air fuel ratio calculated by ECM with the actual air fuel ratio
measured by sensor.
(2)
(25)
(23)
(22)
(21)
(20)
(19)
(18) (17)
(3)
(4)
(5)
(24)
(6)
(7)
(13)
(12)
(16) (15) (14) (11) (10)
(14) Fuel temperature sensor
(15) Fuel level sensor
(16) Fuel pump
(17) Jet pump
(18) Fuel cut valve
(19) Fuel sub level sensor
(20) Fuel tank
(21) Fuel tank pressure sensor
(22) Fuel meter
(23) Combination meter
(24) Fuel injector
(25) Tank pressure switching solenoid valve
GD(STi)-75
GENERAL DESCRIPTION
: A
: B
(8)
(9)
EN-01770