O4 DURAMAX CODE DTC #04 P0302 - Silverado 2500HD Chevrolet Cars & Trucks

Kimberly, Change the spark plug, if you have not done so. Check the links below for a long list of what could cause misfire.
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http://www.obd-codes.com/p0302
P0302 OBD II Trouble Code
Diagnose Engine Misfire

DTC code PO400 could be caused by a clogged EGR valve or EGR tube. try cleaning the EGR valve, tube
DTC code PO171 is fuel system too lean bank 1
DTC code PO174 is fuel system too lean Bank 2
Most likely suspects are O2 sensors, But can be caused by vacuum leaks and also can be Mass airflow sensor (MAF) try cleaning with electrical parts cleaner
DTC code PO 302 is a misfire at cylinder # 2
Check spark plugs and wires
Try cleaning the EGR Valve first along with changing the spark plug first, and see if any codes erase, in other words start with the cheaper fixes first, as some problems can be causing the other other codes

http://www.aboutautomobile.com/DTC/P0302

http://www.aboutautomobile.com/DTC/P0316

replace coils

check for 2 things, CTS, and the injector, reason, if the injector is clogged or misfiring, you can still have and issue, i`m a mobile mechanic, if you`re in the long beach area email me back

If you need further help, reach me via phone at https://www.6ya.com/expert/reginald_d1f35dc049b0256a

Diagnostic Test Code (DTC) C1244 is a "maufacturer-specific" code used by Toyota for this vehicle. Toyta defines this code simply as "DECELERATION SENSOR CIRCUIT."

Possible causes are:
> Faulty ABS deceleration sensor
> Open or short in deceleration sensor circuit
> Defective wiring harness or connectors

The deceleration sensor for your 2004 Toyota Tacoma is located under the passenger seat.

The service 4x4 light coming on indicates problem with the system an DTC'S - diagnostic trouble codes are stored . Before replacing parts have a qualified repair shop do diagnostic's . ! Guessing an replacing parts on electronically controlled systems never fixes cars.
Do you know what DTC'S are ?
DTC B0775
DTC B0780
DTC B0785
DTC B0790
DTC B2725
DTC C0306
DTC C0379
DTC C0387
DTC C0396
DTC C0550
DTC C0569
DTC C0896
DTC P2160 or P2161
Which transfer case does it have ?
Transfer Case - BW 4485-NR3
Transfer Case - MP 1222/1225/1226-NQG
Transfer Case - MP 1625/1626-NQF
Transfer Case - MP 3023-NQH
Transfer Case - NVG 261-NP2

All fault codes can be checked out at http://www.bluejag.co.uk but here are the results for some of yours. You can ignor P1111. Looks like a faulty plug or coil pack cylinder 2

Fault Code:- P1314 Indicates a Power-train fault


The fault is generally due to a problem in the Ignition or Misfire area


Fault Description: Misfire rate catalyst damage -bank 2 NOTE: This DTC will flag only when accompanied by an individual cylinder misfire DTC: P0300 - P0306

Action of ECM:- ECM Default:- Maximum engine speed reduced


After clearing the DTC, complete the Misfire monitor drive cycle
Check for a reoccurrence of fault DTC.

Possible Fault:- Cylinder compression low Worn camshaft / broken valve spring(s) Fuel delivery pressure (low / high) Fuel injector(s) restricted / leaking Fuel injector(s) continuously open Fuel contamination Fuel injector circuit fault(s) (Injector DTCs also flagged) Spark plug failure / fouled / incorrect gap ECM to ignition coil primary circuit fault (Cylinder misfire detected DTC also flagged) Ignition coil failure
Fault Code:- P1316 Indicates a Power-train fault


The fault is generally due to a problem in the Ignition or Misfire area


Fault Description: Misfire excess emission NOTE: This DTC will flag only when accompanied by an individual cylinder misfire DTC: P0300 - P0306

Action of ECM:- none


After clearing the DTC, complete the Misfire monitor drive cycle
Check for a reoccurrence of fault DTC.

Possible Fault:- Cylinder compression low Worn camshaft / broken valve spring(s) Fuel delivery pressure (low / high) Fuel injector(s) restricted / leaking Fuel injector(s) continuously open Fuel contamination Fuel injector circuit fault(s) (Injector DTCs also flagged) Spark plug failure / fouled / incorrect gap ECM to ignition coil primary circuit fault (Cylinder misfire detected DTC also flagged) Ignition coil failure

Fault Code:-
P0302 Indicates a Power-train fault


The fault is generally due to a problem in the Ignition or Misfire area


Fault Description: Misfire detected ?€" cylinder 2

Action of ECM:- none


After clearing the DTC, complete the Misfire monitor drive cycle
Check for a reoccurrence of fault DTC.

Possible Fault:- Refer to P0300 Possible Causes

P0302 is a misfire in cylinder #2. When was the last time you changed spark plugs? That's the most common cause of a misfire.

it means you reader does not decode the codes for you! you must look it up on the internet or ask the dealer! good luck!

DTC code P0421 is the O2 sensor that indicates a an issue with the Catalytic Converter. Replace the O2 sensor to the Catalytic Converter "the one after Converter" It's common for the sensor to fail and you can pick one up from Auto Zone and they will have the step by step instructions to replacing the O2 sensor. 
DTC code P0302 Indicates a misfire on cylinder #2. Address the spark plug, spark plug wire, and injector. Look for any damages and try running some fuel injector cleaner through the fuel system to clean out the injectors. 
Good luck and hope this helps.