Engine-Codes - Pontiac - P0300 Pontiac

P0300 Pontiac Code - Engine Misfire Detected

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- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the Code P0300 Pontiac?

  • Faulty spark plug (s)
  • Faulty ignition coil (s)
  • Clogged or faulty fuel injector (s)
  • Intake air leak
  • Fuel injectors harness is open or shorted
  • Fuel Injectors circuit poor electrical connection
  • Ignition coils harness is open or shorted
  • Ignition coils circuit poor electrical connection
  • Insufficient cylinders compression
  • Incorrect fuel pressure

How to Fix the P0300 Pontiac Code?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

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Code P0300 Pontiac Tech Notes

The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are commonly caused by multi-cylinder misfiring. If no leak is found the next step is to replace the spark plugs. If the problem persists more tests need to be done to diagnose the problem, see "Possible Causes".

There are Factory Service Bulletin for the following Pontiac models:

2000-2001 Pontiac Transport
2000-2002 Pontiac Firebird
2000-2008 Pontiac Bonneville
2000-2008 Pontiac Grand Am
2000-2008 Pontiac Grand Prix
2000-2008 Pontiac Sunfire
2001-2008 Pontiac Aztek
2002-2008 Pontiac Montana
2000-2008 Pontiac Factory Service Bulletin OBDII Code P0300

2005-2006 Pontiac Grand Prix
2005-2006 Pontiac Grand Prix Service Bulletin OBDII Code P0300

What is the Cost to Diagnose the Code P0300 Pontiac?

Labor: 1.0

The cost to diagnose the P0300 Pontiac code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

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What are Code P0300 Pontiac Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Lack/loss of power
  • Hard start
  • Engine hesitation

What Does the P0300 Pontiac Code Mean?

A misfiring cylinder causes slight variations in the rotational speed of the crankshaft. The Engine Control Module (ECM) is able to detect these variations by closely monitoring the crankshaft position sensor signal. The signals of the camshaft position sensors are used to determine which cylinder is misfiring. If the ECM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, the Diagnostic Trouble Code (DTC) will be set. Under certain driving conditions, a misfire rate can be high enough to cause the catalytic converter to overheat, possibly damaging the converter. The Malfunction Indicator Lamp (MIL) flashes when the converter is overheating, damaging conditions are present, and the DTC is set. The DTC will be set when the ECM detects a crankshaft rotation speed variation indicating a misfire rate sufficient to cause emissions levels to exceed a predetermined value or a misfire rate high enough to cause catalyst damage.

P0300 Pontiac Code - Engine Misfire Detected

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