Honda Civic Service Manual page 525

4
The scan tool indicates Dlagnostic Trouble cod€ {DTc} Po4ol: lnsufficient flow in the Exhaust Gas Recirculation
(EGR) svstem.
Doscription
Deterioration (clogging, leakage, etc.) in the EGR line or EGR valve is detected by means of
the changes in MAP before
and after the operation of the EGR valve.
lf deterioration has been detected during two cons€cutive driving cycles, the MIL will come on and
DTC P0401 will be
stored.
Po$ible Causeg
. Clogging. leakage in the EGR line
. Faulty EGR valve
Troubleshooting Flowchart
\
- Tho MIL ht! bacn rgportod on.
-
DTC m40l is 3torod.
Problom vorification:
1. Do the ECM/PCM Reset Proce-
dure.
2. Connect the SCS service con-
nector,
3. Tost-drive under the following
conditions.
-
Without any electrical load
-
Decelerate lrom 55 mPh
(88 km/h)lor at least 5 sec-
onos
lntormiftam f!ilu.a, ayltam ia OK
.t thb time,
- Clo.n tho inttkc mlnifold EGR
port wittr carbursto. clotner.
- Cl.an the pa$lgo insido tho
EGR valvo with crrburator
cloanol or aoglaca tha vllvo.