Getting code P0300

KJ PETERSON

MEMBER
2010 DODGE CHARGER
5.7L
V8
2WD
AUTOMATIC
133,000 MILES

So, I have replaced all 16 plugs and all 8 coil packs and I am getting code p0300. It wouldn't start at first and I pulled all the new plugs and inspected the new packs, all seem to be fine and I actually got her to start and stay running yesterday, but now today she wont start again. I am still getting the p0300 code. Help! What should I do next?

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

Was the code present before the spark plug replacement?

I posted below the possibilities for you to view.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

I would start by checking the fuel pressure to be sure the fuel pump is delivering the correct pressure.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Roy

P0300
Descriptor
Multiple Cylinder Misfire
Probable Causes
Engine Coolant Temperature (ECT) Sensor, Wiring or Connectors
Engine Mechanical System
Fuel Delivery System
Ignition Coil, Wiring, or Connectors
Manifold Absolute Pressure (MAP) Sensor, Wiring, or Connectors
Oxygen Sensor (O2S), Wiring, or Connectors
Powertrain Control Module (PCM)

1. DTC IS ACTIVE
1. Diagnose and repair any other active component or circuit DTCs before continuing with this procedure.
2. Turn the ignition on.
3. With the scan tool, select View DTCs. Copy DTC and Freeze Frame information.
4. Start the engine and allow it to reach operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set.

NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

5. With a scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go To 2

No

Perform the CHECKING FOR AN INTERMITTENT DTC diagnostic procedure. See: Computers and Control Systems > Initial Inspection and Diagnostic Overview > Checking for an Intermittent DTC.

2. DIAGNOSTIC INSPECTION

NOTE: Anything that affects the speed of the crankshaft can cause this DTC to set. When a misfire is detected, the PCM will shut down the injector control circuit for the misfiring cylinder. Misfire may occur and may not be caused by component failure. Any of the following conditions can cause a misfire.

Inspect the engine for any of the following conditions:

Worn serpentine belt
Misalignment or binding water pump, P/S pump or A/C compressor pulleys
Improper CKP, CMP, or MAP Sensor mounting.
Poor connector/terminal to component connection for CKP sensor, CMP sensor, MAP sensor, throttle body, fuel injector, ignition coil, etc.
Corroded PCM power or ground circuits.
Vacuum leaks.
Restriction in the air induction or exhaust system.
Internal engine component malfunction.
Moisture on ignition system components
Insufficient fuel
Low quality fuel
Manual transmission bog
Towing overload

Were any problems found?

Yes

r as necessary.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

Go To 3

3. CHECKING THE FUEL DELIVERY SYSTEM
1. Perform the diagnostic procedures for FUEL PRESSURE LEAK DOWN and FUEL DELIVERY SYSTEM OUTPUT - FLOW TEST. See: Computers and Control Systems > Component Tests and General Diagnostics > Checking the Fuel Delivery System.

Were any problems found?

Yes

Repair as necessary.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

Go To 4

4. CHECKING THE IGNITION COIL OPERATION
1. Perform the diagnostic procedure for CHECKING THE IGNITION COIL OPERATION. See: Computers and Control Systems > Component Tests and General Diagnostics > Checking the Ignition Coil Operation.

Were any problems found?

Yes

Repair as necessary.
erform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

Go To 5

5. CHECKING THE ENGINE COOLANT TEMPERATURE SENSOR OPERATION
1. Perform the diagnostic procedure for CHECKING THE ENGINE COOLANT TEMPERATURE SENSOR OPERATION. See: Computers and Control Systems > Component Tests and General Diagnostics > Checking the Engine Coolant Temperature Sensor Operation.

Were any problems found?

Yes

Repair as necessary.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

Go To 6

6. CHECKING THE MAP SENSOR OPERATION
1. Perform the diagnostic procedure for CHECKING THE MAP SENSOR OPERATION. See: Computers and Control Systems > Component Tests and General Diagnostics > Checking the MAP Sensor Operation.

Were any problems found?

Yes

Repair as necessary.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

o To 7

7. CHECKING THE OXYGEN SENSOR OPERATION
1. Perform the diagnostic procedure for CHECKING THE OXYGEN SENSOR OPERATION. See: Computers and Control Systems > Component Tests and General Diagnostics > Checking the Oxygen Sensor Operation.

Were any problems found?

Yes

Repair as necessary.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

Go To 8

8. CHECKING THE ENGINE MECHANICAL SYSTEM
1. Perform the diagnostic procedure for CHECKING THE ENGINE MECHANICAL SYSTEM. See: Computers and Control Systems > Component Tests and General Diagnostics > Checking the Engine Mechanical System.

Were any problems found?

Yes

Repair as necessary.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

Go To 9

9. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors relative to the components tested in this procedure.
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to the components tested in this procedure and wiggle test the wiring and connectors.
5. Look for the data to change or for a DTC to set during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

Repair as necessary.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.

No

Replace and program the PCM.
Perform the PCM VERIFICATION TEST. See: A L L Diagnostic Trouble Codes ( DTC ) > Verification Tests > PCM Verification Test.