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Dodge Caliber. Manual - part 743

P0301-CYLINDER 1 MISFIRE

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
Any time the engine is running, and the adaptive numerator has been successfully updated.

•

Set Condition:
When more than 1% misfire rate is measured during two trips. Three good trips to clear the MIL.

Possible Causes

INTERMITTENT DTC

(K343) FUSED MAIN RELAY OUTPUT CIRCUIT

(K344) FUSED MAIN RELAY OUTPUT CIRCUIT

(K11) INJECTOR 1 CONTROL CIRCUIT

(K19) COIL 1 CONTROL CIRCUIT

IGNITION WIRE

SPARK PLUG

FUEL PUMP INLET STRAINER PLUGGED

FUEL SUPPLY LINE RESTRICTED

FUEL PRESSURE LEAK DOWN

FUEL INJECTOR 1

IGNITION COIL 1

FUEL PUMP MODULE

INTERNAL ENGINE COMPONENT

POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).

Diagnostic Test

DTC IS ACTIVE

Start the engine and allow it to reach operating temperature.

With the scan tool, monitor the View DTC screen.

Is the status Active for this DTC?

Yes

>> Go to 2

>> Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE -

DIAGNOSIS AND TESTING)

VISUAL INSPECTION

NOTE: Anything that affects the speed of the crankshaft can cause a misfire DTC to set.
Visually inspect the engine for any of the following conditions:

- Worn serpentine belt

- Binding engine driven accessories: A/C compressor, P/S pump, water pump.

- Misalignment of the Water pump, P/S pump or A/C compressor pulleys

- Corroded PCM power or ground circuits.

- Improper CKP, CMP, MAP, or TP Sensor mounting.

- Poor connector/terminal to component connection for CKP, CMP, MAP, or TP sensor, fuel injector, ignition coil, etc.

- Vacuum leaks.

- Restriction in the air induction or exhaust system.

ENGINE ELECTRICAL DIAGNOSTICS - GPEC

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- Internal engine component malfunction.

Were any of the above conditions present?

Yes

>> Repair as necessary.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

>> Go to 3

(K343) FUSED MAIN RELAY OUTPUT CIRCUIT

Turn the ignition off.

Disconnect the Fuel Injector 1 connector.

Turn the ignition on.

Using a 12 volt test light connected to ground, check the (K343) Fused
Main Relay Output circuit in the Fuel Injector 1 harness connector.

NOTE: The test light should be illuminated and bright. Compare
the brightness to that of a direct connection to the battery.

Is the test light illuminated and bright?

Yes

>> Go to 4

>> Repair the (K343) Fused Main Relay Output circuit for high

resistance or a short to ground.

Perform the PCM Verification Test Ver. 1 (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING)

(K344) FUSED MAIN RELAY OUTPUT CIRCUIT

Turn the ignition off.

Disconnect the Ignition Coil 1 connector.

Turn the ignition on.

Using a 12 volt test light connected to ground, check the (K344) Fused
Main Relay Output circuit in the Ignition Coil 1 harness connector.

NOTE: The test light should be illuminated and bright. Compare
the brightness to that of a direct connection to the battery.

Is the test light illuminated and bright?

Yes

>> Go to 5

>> Repair the (K344) Fused Main Relay Output circuit for high

resistance or a short to ground.

Perform the PCM Verification Test Ver. 1 (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING)

IGNITION SYSTEM OPERATION

Turn the ignition off.

Remove the Ignition Coil 1.

Connect the Ignition Coil 1 harness connector.

NOTE: Leave the Fuel Injector 1 harness connector disconnected.
Install a spark tester on Ignition Coil 1.

While cranking the engine, observe the spark coming from the spark tester.

NOTE: A crisp blue spark that is able to jump the gap of the spark tester should be generated.

Is good spark present?

Yes

>> Go to 6

>> Go to 15

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ENGINE ELECTRICAL DIAGNOSTICS - GPEC

NOTE: Connect the Fuel Injector 1 harness connector before continuing.

SPARK PLUG

Turn the ignition off.

Remove the spark plug.

Inspect the spark plug for the following conditions:

- Cracks

- Carbon tracking

- Foreign material

- Spark plug gap out of specifications

- Loose or broken electrode

NOTE: To check the electrode, lightly tap the bottom of the spark plug on a solid surface. The electrode
should not move.

Were any problems found?

Yes

>> Replace the spark plug.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

>> Go to 7

FUEL PRESSURE OUT OF SPECIFICATION

NOTE: Before continuing, install any components that were removed for testing, and connect all harness
connectors.

WARNING: The fuel system is under a constant pressure, even with the engine off. Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow
these instructions can result in personal injury or death.
Turn the ignition off.

Install a fuel pressure gauge to the fuel rail.

Start the engine and observe the fuel pressure reading.

NOTE: The fuel pressure specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

Select the conclusion that best matches the fuel pressure reading:

Within Specification

Go to 8

Below Specification

Go to 13

Above Specification

Replace the fuel filter/pressure regulator.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

FUEL INJECTOR LEAK DOWN

NOTE: Before continuing, inspect the fuel delivery system for external leaks or damage. Repair or replace
any leaking parts in accordance with the Service Information.
Turn the ignition off.

Install special tool #6539 (5/16

) or #6631 (3/8

) fuel line adapter.

Install the fuel pressure gauge.

Start the engine and allow the fuel system to reach maximum pressure.

Turn the ignition off.

ENGINE ELECTRICAL DIAGNOSTICS - GPEC

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NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).
Using special tool #C4390, Hose Clamp Pliers, pinch the rubber fuel line between the fuel pressure gauge and the
engine.

Monitor the fuel pressure gauge for a minimum of 5 minutes.

NOTE: The pressure should not drop below 241 KPa (35 psi).

Does the pressure drop below the listed specification?

Yes

>> Replace the leaking fuel injector(s).

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

>> Go to 9

FUEL INJECTOR OPERATION

CAUTION: After each fuel injector actuation, start the engine to clear the cylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool #C4390.

Start the engine and allow the fuel pressure to reach maximum pressure.

Ignition on, engine not running.

Using the scan tool, actuate the Fuel Injector 1 control.

Monitor the fuel pressure gauge.

Does the fuel pressure drop after the injector is actuated?

Yes

>> Go to 10

>> Go to 11

NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.

10.

INTERNAL ENGINE COMPONENT

Check for any of the following conditions/mechanical problems.

ENGINE VACUUM - must be at least 13 inches in neutral

ENGINE VALVE TIMING - must be within specifications

ENGINE COMPRESSION - must be within specifications

ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.

ENGINE PCV SYSTEM - must flow freely

TORQUE CONVERTER STALL SPEED - must be within specifications

POWER BRAKE BOOSTER - no internal vacuum leaks

FUEL - must be free of contamination

CAM LOBES - must not be worn excessively

CYLINDER LEAKAGE TEST - must be within specifications

VALVE SPRINGS - must not be weak or broken

Were any problems found?

Yes

>> Repair as necessary.

Perform the PCM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

>> Go to 17

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ENGINE ELECTRICAL DIAGNOSTICS - GPEC

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