SsangYong Musso. Manual - part 183

1F-316 ENGINE CONTROLS

SSANGYONG Y158

DIAGNOSTIC TROUBLE CODE (DTC) P0304

CYLINDER 4 MISFIRE

Circuit Description

The Engine Control Module (ECM) monitors the crank-
shaft and camshaft positions to detect if the engine is
misfiring. The ECM looks for a quick drop in crankshaft
speed. It may take between one to several tests to store
a Diagnostic Trouble Code (DTC) and illuminate the
Malfunction Indicator Lamp (MIL). Under light misfire
conditions, it may also take more than one trip to set a
DTC. Severe. Misfire will flash the MIL, indicating that
catalyst damage is possible.

Misfire of cylinder 4 is monitored by cylinder selective
engine roughness measuring. The actual roughness value
is compared with the actual (emission and catalyst
damage) threshold.

Conditions for Setting the DTC

•••••

DTCs P0101, P0102, P0103, P0111, P0112, P0113,
P0335, P0336, P0341, P0351, P0352, P0353 (3.2L
DOHC) and P0600 are not set.

•••••

Counting of misfire within 1000 revolutions and
exceeding misfire EC emissions threshold is 70 for
A/T and 102 for M/T (2.3L DOHC)

•••••

Counting of misfire within 1000 revolutions and
exceeding misfire EC emissions threshold is 3.5%
(3.2L DOHC)

•••••

Counting of misfire within 200 revolution and

exceeding misfire catalyst damage is greater than
18 weighted (MIL BLINK after 1st exceed).

•••••

Misfire starting end (500 rpm) is reached.

•••••

At least one injector is reversible shut down by limiter
is not present.

•••••

Engine speed is between 500 and 5700 rpm (2.3L
DOHC).

•••••

Engine speed is between 450 and 4000 rpm (3.2L
DOHC).

•••••

Load gradient is between 0.05 and -0.05.

•••••

At least two injectors are irreversible shut down or
marked for shut down is not present.

•••••

Load below threshold is between 0.17 and 0.34 (2.3L
DOHC).

•••••

Load below threshold is between 0.18 and 0.35 (3.2L
DOHC).

•••••

Increment wheel compensation precess is successful
finished.

•••••

Gear shift (A/T) is not active.

•••••

Crankshaft/camshaft synchronizationis no fault.

•••••

Tip down during cruise control active is not active.

•••••

Tank level is greater than 13 liters.

•••••

Clutch lever is greater than 13 liters.

YAB1F180

ENGINE CONTROLS 1F-317

SSANGYONG Y158

Action Taken When the DTC Sets

•••••

The MIL will illuminate after two consecutive driving
cycles in which the diagnostic runs with the fault ac-
tive.

•••••

The MIL will illuminate immediately and flash if the
catalyst darnage misfire is present.

•••••

The ECM will record operating conditions at the time
the diagnostic fails. This information will be stored in
the Freeze Frame and Failure Records buffers.

•••••

A history DTC is stored.

Conditions for Clearing the MIL/DTC

•••••

The MIL will turn off after three consecutive driving
cycles in which the diagnostic runs without a fault.

•••••

A history DTC will clear after 40 consecutive warm-
up cycles without a fault.

•••••

The DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

An intermittent can also be the result of a defective re-
luctor wheel. Remove the CKP sensor and inspect the
reluctor wheel through the sensor mount hole. Check
for porosity and the condition of wheel.

The Scan tool active misfire counts should pick up an
intermittent misfire problem. Watch the scan tool misfire
counter. When a specific cylinder misfires under certain
load, conditions may be duplicated in the stall.

Test Description

The number(s) below refer to specific step(s) on the
diagnostic table.

1. Euro On-Board Diagnostic (EOBD) System Check

prompts the technician to complete some basic
checks and store the freeze frame and failure records
data on the scan tool if applicable. This creates an
electronic copy of the data taken when the
malfunction occurred. The information is then stored
on the scan tool for later reference.

3. A visual/physical inspection should include checking

the following components:

•••••

The wiring for proper connections, pinches or cuts.

•••••

The ECM grounds for being clean and tight.

•••••

The vacuum hoses for splits, kinks, and improper
connections as shown on the Vehicle Emission
Information label.

•••••

Check thoroughly for any type of leak or restric-
tion.

•••••

Check for air leaks at the throttle body mounting
area and intake manifold sealing surface.

5. When all the accumulators are relatively equal, the

misfire is being caused by something that affects
the entire engine. When they are not, the misfire is
being caused by something that is specific to two
or more cylinders.

6. Whenever the misfire is not present, operating the

vehicle may be necessary to duplicate the condi-
tions in the Freeze Frame Data in order to detect
misfire. Depending on the engine load, the condi-
tions may have to be maintained for up to 20 sec-
onds. When the misfire is present. A history misfire
counter will store the number of misfires that have
occurred until the DTC is cleared.

8. Check fuel for water, alcohol, etc. (Water in the fuel

can cause an occasional random misfire.)

9. A basic engine problem that affects all cylinders is

the only possibility at this point. (Cam timing, throttle
body leak, restricted air flow, etc.)

11. Tests the ignition system voltage output using a

spark tester.

12. Replace any spark plugs that are worn, cracked or

fouled.

13. Checks for voltage at the ignition feed circuits.

18. Whenever the driver circuit is shorted to ground,

the light will be on steady. When the driver circuit is
shorted to voltage or open, the light will be off.

19. Since voltage is supplied to the fuel injector on a

single circuit, the malfunction can only be a poor
connection or open in the fuel injector harness. An
open before the harness would result in an ”Engine
Cranks But Will Not Run” complaint.

24. Before replacing the ECM, check terminals for im-

proper mating, broken locks, or physical damage
to the wiring harness. The replacement ECM must
be reprogrammed. Refer to the latest Techline proce-
dure for ECM reprogramming.

1F-318 ENGINE CONTROLS

SSANGYONG Y158

Perform the Euro On-Board Diagnostic (EOBD) System
Check.
Is the system check complete?

1. Turn the ignition ON, with the engine OFF.
2. Install a scan tool.
Is an Ignition Coil, injector or P0300 DTC set?
1. Perform a visual/physical inspection.
2. Make any repairs that are necessary.
Is the repair complete?
Start the engine and allow it to idle.
Are any Misfire Current counters incrementing?
Are all counters equal (within a percentage of each
other)?
1. Turn the ignition ON, with the engine OFF.
2. Review the Freeze Frame data, and note the

parameters.

3. Operate the vehicle within the Freeze Frame

conditions and conditions for setting this DTC as
noted.

Are any Misfire Current counters incrementing?
1. Turn the ignition OFF.
2. Install a fuel pressure gauge to the fuel rail.
3. Observe the fuel pressure with the engine running.
Is the fuel pressure within the specified value?
Check the fuel for contamination.
Is the fuel OK?
Check for a basic engine problem and repair as
necessary.
Is the repair complete?
Replace the contaminated fuel.
Is the repair complete?
1. Turn the ignition OFF.
2. Disconnect the fuel injector harness connector.
3. Install a spark tester on cylinder #4 spark plug cable.
4. Crank the engine and check for spark.
Is a spark observed on the spark plug cable?
Replace the malfunctioning spark plug if necessary.
Is the repair complete?
1. Turn the engine OFF.
2. Disconnect the cylinder #4 fuel injector connector

from the injectors.

3. Install an injector test light on the injector harness

connector, terminal 2.

4. Crank the engine and note the test light.
Does the injector test light blink?
Perform the Fuel Injector Balance Test.
Are the fuel injectors OK?

Step

Action

Value(s)

Yes

DTC P0304 Cylinder 4 Misfire

Go to Step 5

Go to Step 6

Go to Step 9

Go to Step 10

Go to Step 27

Go to Step 2

Go to “Euro

On-Board

Diagnostic

System Check”

Go to Step 9

Go to Step 16

Go to Step 27

Go to Step 14

Go to Step 15

Go to Step 27

Go to Step 13

Go to Step 12

Go to Step 20

320 - 380 kPa

(46 - 55 psi)

Go to Step 8

Go to “Fuel

System

Diagnosis”

Go to Step 5

Go to

"Diagnostic

Aids"

Go to Step 27

Go to Step 4

Go to Step 7

Go to Step 11

Go to

applicable

DTC table

Go to Step 3

ENGINE CONTROLS 1F-319

SSANGYONG Y158

1. Disconnect the injector test light.
2. With a test light connected to ground, probe the

ignition feed terminal 1 of the injector harness
connector for each cylinder that had misfire.

3. Crank the engine.
Does the test light illuminate?
Replace any malfunctioning fuel injectors.
Is the repair complete?
Check the affected fuel injector driver circuit at terminals
62 (66-2.3L DOHC) for an open, short, or short to
voltage.
Is a problem found?
Repair the open or the shorted fuel injector driver circuit.
Is the repair complete?
Repair the open ignition feed circuit between the fuel
injector harness connector and the fuel injector
connector.
Is the repair complete?
Measure the resistance of the spark plug cable that the
spark plug tester did not spark.
Is the resistance of the spark plug cable between the
specified value?
Inspect the Engine Control Module (ECM) connector
and connections.
Are the connections OK?
Check the affected cylinders ignition control circuit for
an open or short and repair as necessary.
Is the repair complete?
Repair the connector or connections.
Is the repair complete?
1. Turn the ignition OFF.
2. Replace the ECM.
Is the repair complete?
Replace the spark plug cable.
Is the repair complete?
Replace the faulty ignition coil.
Is the repair complete?
1. Using the scan tool, clear the DTCs.
2. Start the engine and idle at normal operating

temperature.

3. Operate the vehicle within the conditions for setting

this DTC as supported in the text.

Does the scan tool indicate that this diagnostic ran
passed?
Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?

Step

Action

Value(s)

Yes

DTC P0304 Cylinder 4 Misfire (Cont’d)

Go to Step 17

Go to Step 19

Go to Step 27

Go to Step 22

Go to Step 23

Go to Step 27

Go to Step 26

Go to Step 27

Go to Step 18

Go to Step 24

Go to Step 27

Go to Step 24

Go to Step 28

Go to Step 2

Go to Step 27

1.8 - 2.2 k

Ω

Go to Step 21

Go to Step 25

Go to Step 27

Go to

applicable

DTC table

System OK

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