Honda Civic Service Manual page 277

PGM-FI System
DTC Troubleshooting (cont'dl
DTC P0171: Fuel System Too Lean
DTC P0172: Fuel System Too Rich
NOTE: lf some of the DTCS listed below are stored at
the same time as DfC PO17'l and/ot PO172,
troubleshoot those DTCS first, then recheck for P0171
andlot P0112.
P 0 1 0 7 , P 0 1 0 8 . P 1 1 2 8 . P 1 1 2 9 : M a n i f o l d a b s o l u t e
p r e s s u r e ( M A P ) s e n s o r
P1 162. P1 166, P 1 167: 4,,/F sensor (Sensor 1 ) heater
P 0 1 3 7 , P 0 1 3 8 : S e c o n d a r y H O 2 S ( S e n s o r 2 )
P014'l: Secondary HO2S (Sensor 2) heater
P1259: VTEC system
1 . C h e c k t h e f u e l p r e s s u r e ( s e e p a g e 1 1 - ' 1 4 5 ) .
ls luel pressure OK?
YES Go to step 2.
NO Check these items:
. lf the pressure is too high, replace the fuel
p r e s s u r e r e g u l a t o r ( s e e p a g e 1 1 - 1 5 2 ) . 1
. l f t h e p r e s s u r e i s t o o l o w . c h e c k t h e f u e l p u m p ,
the fuel feed pipe, the fuel filter, and replace the
f u e l p r e s s u r e r e g u l a t o r ( s e e p a g e 1 1 - 1 5 2 ) . I
2. Start the engine. Hold the engine at 3,000 rpm with
no load (in neutral) until the radiator fan comes on.
11-70
3. Turn the ignition switch OFF.
4. With a vacuum pump, apply vacuum to the
evaporative emission (EVAP) canister purge valve
(A) from the evaporative emission (EVAP) canister
s i d e .
'
A973AX-041-XXXXX
Does it hold vacuum?
YES-Check the engine valve clearances and adjust
if necessary, lf the valve clearances are OK, replace
t h e i n j e c t o r s ( s e e p a g e 1 1 - 1 1 1 ) . 1
NO-Replace the EVAP canister purge valve.l