TOPDON DTC P0300 Diagnostic System Instructions

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YMMS: 2008 Saturn Aura XR
Engine: 3.6L Eng
VIN:
DTC P0300-P0306
Instructions

DIAGNOSTIC INSTRUCTIONS

• Perform the Diagnostic System Check – Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• Diagnostic Procedure Instructions provide an overview of each diagnostic category.

DTC DESCRIPTORS

DTC P0300
Engine Misfire Detected
DTC P0301
Cylinder 1 Misfire Detected
DTC P0302
Cylinder 2 Misfire Detected
DTC P0303
Cylinder 3 Misfire Detected
DTC P0304
Cylinder 4 Misfire Detected
DTC P0305
Cylinder 5 Misfire Detected
DTC P0306
Cylinder 6 Misfire Detected

CIRCUIT/SYSTEM DESCRIPTION

The engine control module (ECM) uses information from the crankshaft position (CKP) sensor in order to determine when an engine misfire is occurring, and uses information from the camshaft position (CMP) sensor in order to determine which cylinder is misfiring. By monitoring variations in the crankshaft rotation speed for each cylinder, the ECM is able to detect individual misfire events. If the ECM detects a misfire rate sufficient to cause the emission levels to exceed mandated standards, DTC P0300 sets.
Under certain driving conditions, a misfire rate can be high enough to cause the 3-way catalytic converter (TWC) to overheat, possibly damaging the converter. The malfunction indicator lamp (MIL) will flash ON and OFF when converter overheating, damaging conditions are present and DTC P0300 is set.
DTCs P0301-P0306 correspond to cylinders 1-6. If the ECM is able to determine that a specific cylinder is misfiring, the DTC for that cylinder may also set.

CONDITIONS FOR RUNNING THE DTC

• DTCs P0016, P0101, P0102, P0103, P0107, P0108, P0116, P0117, P0118, P0120, P0121, P0122, P0123, P0128, P0220, P0222, P0223, P0335, P0336, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2135, or P2138 are not set.

• DTC P0315 is not set and engine speed is between 525-6,000 RPM.
  OR
  DTC P0315 is set and engine speed is less than 1,000 RPM.

• The ignition voltage is between 9-18 volts.

• The engine coolant temperature (ECT) parameter is between -7 and +129°C (+19 and +264°F).

• If the ECT is less than -7°C (+19°F) at engine start-up, this diagnostic is disabled until the ECT is more than +21°C (+69°F).

• The fuel level is more than 10 percent.

• The antilock brake system (ABS) and the traction control system (TCS) are not active or detecting rough road.

• The ECM is not in fuel shut-off or decel fuel cut-off mode.

• The power management is not active.

• Excessive drive wheel slip is not detected.

• DTCs P0300-P0306 run continuously when the above conditions are met.

DIAGNOSTIC AIDS

• A misfire may only occur when the engine is under a load or when the engine is cold.

• A misfire DTC could be caused by an excessive vibration from sources other than the engine.
  Inspect for the following possible sources:

  • A tire or wheel that is out of round or out of balance
  • Variable thickness brake rotors
  • An unbalanced drive shaft
  • Certain rough road conditions
  • A damaged accessory drive component or belt
  • A damaged reluctor wheel

• The Crankshaft Position System Variation Learn procedure may need to be performed. Refer to Crankshaft Position System Variation Learn .

REFERENCE INFORMATION

Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 26792 Spark Tester

CIRCUIT/SYSTEM VERIFICATION

1. Verify that no other DTCs are set.
   1. If a DTC is set, refer to Diagnostic Trouble Code (DTC) List – Vehicle .

2.  Engine idling, verify there is no abnormal engine noise.
   1. If there is an abnormal engine noise, refer to Symptoms – Engine Mechanical .

3. Observe the Misfire Current Counters with a scan tool. The Misfire Current Counters should not be incrementing. Random misfires that are not steadily incrementing may be normal.

4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

CIRCUIT/SYSTEM TESTING

1. Verify that the following conditions do not exist:
   1. The fuel injector wire harness electrical connectors are connected to the improper fuel injectors.
   Refer to Engine Controls Schematics .
   2. Engine vacuum leaks
   3. Fuel pressure that is too low or too high-Refer to Fuel System Diagnosis .
   4. Contaminated fuel-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
   5. Restricted exhaust system-Refer to Restricted Exhaust .

2. Ignition OFF, remove the ignition coil from the misfiring cylinder, leaving the electrical connector connected.

3. Install the J 26792 to the boot of an ignition coil and ground.
   IMPORTANT: An erratic or weak spark is considered a no spark condition.

4. Attempt to start the engine and observe the J 26792 . The spark tester should spark.
   1. If there is no spark, refer to Electronic Ignition (EI) System Diagnosis for diagnosis of the ignition coil.

5. Ignition OFF, remove the spark plug from the misfiring cylinder. Verify that the following conditions do not exist with the spark plug:
   1. Gas, coolant, or oil fouled
   2. Cracked, worn, incorrectly gapped-Refer to Spark Plug Inspection .
   1. If there is a condition with the spark plug, replace the spark plug.

6. Exchange the spark plug with another cylinder that is operating correctly.

7. Operate the engine under the conditions in which the misfire occurred. This may include putting the engine under a load, turning on the A/C, seat heaters, and rear window defog. Observe the Misfire
   Current Counters with a scan tool. The misfire should not follow the spark plug exchange.
   1. If the misfire follows the spark plug, replace the spark plug.

8. If all conditions test normal, test or inspect for the following:
   1. A lean or rich fuel injector-Refer to Fuel Injector Diagnosis (W/CH47976) or Fuel Injector
   Diagnosis (w/Tech 2) .
   2. An engine mechanical condition-Refer to Symptoms – Engine Mechanical .

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Aug 9, 2021
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