Acura RL (1996-2004 year). Manual — part 382

Troubleshooting Flowchart

— The MIL has been reported on.
— DTC P1201 through P1206 or

P1301 through P1306 is indi-
cated.

Problem verification:

1. After checking the freeze data,

do the PCM Reset Procedure.

2. Connect the SCS service con-

nector.

3. Test-drive the car several times

in the range of the freeze data.

Is any misfire DTC indicated?

Does the misfire occur in the other
cylinder whose spark plug was
exchanged?

NO

Check for ignition coil malfunction:

1. Exchange the ignition coil from

the problem cylinder with one
from another cylinder.

2. Test-drive the car several times

in the range of the freeze data.

Is any misfire DTC indicated?

YES

Does the misfire occur in the other

cylinder whose ignition coil was
exchanged?

NO

(To page

11-98

)

NOTE:
• If there is no freeze data of misfiring,

just clear the DTC.

• If there is no freeze data of misfiring,

test drives under various conditions are

necessary.

Intermittent misfire due to spark
plug fouling, etc. (firing is OK at

this time).

Replace the faulty spark plug.

Intermittent misfire due to bad
contact in the ignition coil con-
nector (firing is OK at this time).

Replace the faulty ignition coil.

YES

NO

YES

1. Exchange the spark plug from

the problem cylinder with one

of another cylinder.

2. Test-drive the car several times

in the range of the freeze data.

YES

NO

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PGM-FI System

Misfire Detected in One Cylinder (cont'd)

(From page

11-97

)

Check the injector function:

Listen for a clicking sound at the
injector in the problem cylinder.

Does it click?

NO

YES

Check for an open or short in the
harness between the PCM and

the injector.

Are the wires OK?

Check for injector malfunction:

1. Exchange the injector from the

problem cylinder with one

from another cylinder.

2. Let the engine idle for 2 min-

utes.

3. Test-drive the car several times

in the range of the freeze data.

Repair open or short in the wire.

YES

— Replace the injector.
— Substitute a known-good PCM

and recheck (see page

11-42

for immobilizer information). If
symptom/indication goes
away, replace the original

PCM.

NOTE: If there is no freeze data of mis-

firing, test drives under various condi-
tions are necessary.

Is any misfire DTC indicated?

YES

Intermittent misfire due to bad
contact in the injector connector
(firing is OK at this time).

Does the misfire occur in the other

cylinder whose injector was
exchanged?

Replace the faulty injector.

NO

(To page

11-99

)

YES

NO

NO

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(From page

11-98

)

Check the ignition system wire
harness:
Check the following wires:
• between the PCM and ICM
• between the ignition coil and

ICM

• between the ignition coil and

battery

• between the ignition coil and

spark plug voltage detection

module
(see Electrical Connections and

section 4

)

Are the wires OK?

YES

Check for ICM malfunction:
Substitute a known-good ICM
and recheck.

Does misfire occur?

Repair short or open in the wire.

Replace the ICM.

Check the following items
— Cylinder leak-down

— Compression

YES

NO

NO

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PGM-FI System

Random Misfire

The scan tool indicates Diagnostic Trouble Code (DTC) P0300*

3

,

P1300*

4

and some of P1201 - P1206 or some of P1301 - P1306:

Random misfire.

Description
Misfire detection is accomplished by monitoring the voltage of the spark plug with the spark plug voltage sensor which is
built in to the ignition coil.
If misfiring strong enough to damage the catalyst is detected, the MIL will blink during the time of its occurrence, and DTC
P1300*

3

or P0300*

4

, some of DTCs P1201 through P1206 or some of DTCs P1301 through P1306 will be stored. Then, after

misfire has ceased, the MIL will come on and stay on whenever the ignition switch is ON (II).
If misfiring that increases emissions is detected during two consecutive driving cycles, the MIL will come on, and DTC
P1300*

3

or P0300*

4

, some of DTCs P1201 through P1206 or some of DTCs P1301 through P1306 will be stored.

NOTE: If some of the DTCs listed below are stored at the same time as a misfire DTC, troubleshoot those DTCs first, then

troubleshoot the misfire DTC.

P0106*

1

, P1128*

2

, P1129*

2

: MAP sensor

P0171, P0172, P0174, P0175: Fuel metering
P0401, P1491, PU98: EGR system
P0335, P0336, P1336, P1337, P1381, P1382, P1386, P1387: CKP/CYP sensor
P0505: Idle Control System
PI508: IAC valve
*1: '96 model only
*2: '97 - 01 models
*3: '96 - 97 models
*4: '98 - 01 models

Possible Cause

Fuel pump insufficient fuel pressure, amount of flow
Fuel line clogging, blockage, leakage
Fuel filter clogging
Fuel pressure regulator stuck open
EGR system malfunction
Ignition coil wire open, leakage
Ignition control module malfunction
MAP sensor range/performance, poor response*

1

IAC valve malfunction
Fast idle thermo valve malfunction
Carbon deposits on valves
Compression low
Gasoline does not meet Owner's Manual spec., lack of fuel

Troubleshooting

By test-driving, determine the conditions during which misfire occurs. Depending on these conditions, test in the order

described in the table below.

NOTE: If misfire doesn't recur, some possible causes are fuel that doesn't meet owner's manual spec, lack of fuel, carbon

deposits on spark plug, etc.

11-166 11-69 section 4 section 4 section 6 11-102

and

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