Random Misfire - Honda 2002 Accord Manual

PGM-FI System
DTC Troubleshooting (cont'd)
DTC P0300: Random Misfire
and A n y Combination of the Following:
DTC P0301: No. 1 Cylinder Misfire
DTC P0302: No. 2 Cylinder Misfire
DTC P0303: No. 3 Cylinder Misfire
DTC P0304: No. 4 Cylinder Misfire
NOTE:
• If the misfiring is frequent enough to trigger detection of increased emissions during t w o consecutive driving cycles,
the MIL will come o n , and DTC P0300 (and some c o m b i n a t i o n of P0301 t h r o u g h P0304) will be stored.
• If the misfiring is frequent enough to damage the catalyst, the MIL will blink whenever the misfiring occurs, and DTC
P0300 (and some combination of P0301 through P0304) w i l l be stored. W h e n the misfiring stops, the MIL w i l l remain
on.
1. Troubleshoot the f o l l o w i n g DTCs first, if any of t h e m w e r e stored along w i t h the r a n d o m misfire DTC(s):
P0107, P0108, P1128, P1129: MAP Sensor
P0171, P0172: Fuel metering
P0401, P1491, P1498: EGR system
P0505: Idle control system
P1259: VTEC System (F23A1, F23A4 engine)
P1361, P1362: TDC sensor
P1381, P1382: CYP sensor
P1519: IAC valve
2. Test-drive the vehicle to verify the s y m p t o m .
3. Find the s y m p t o m in the chart below, and do the related procedures and checks, in the order listed, until you find
the cause.
S y m p t o m Procedure Also check for:
Random misfire only at
l o w RPM and under load
1. Check fuel pressure (see page 11-115).
2. Inspect the i g n i t i o n distributor housing.
• Low compression
• Low quality fuel
• Correct EGR valve
function
Random misfire only
during acceleration
1. Inspect and test ignition wires (see page 4-25).
2. Inspect the i g n i t i o n distributor housing.
3. Check fuel pressure (see page 11-115).
4. Test the ignition coil (see page 4-24).
5. Test the ignition control module (see page 4-23).
Malfunction in the
VTEC system (F23A1,
F23A4 engine) (see
page 6-7)
Random misfire at high
RPM and load, or under
random conditions
1. Check fuel pressure (see page 11-115).
2. Inspect and test ignition wires (see page 4-25).
3. Inspect the i g n i t i o n distributor housing.
4. Test the ignition coil (see page 4-24).
5. Test the ignition control module (see page 4-23).
Correct valve
clearance (see page
6-14)
11-70