P0300

On Board Diagnosis Logic:

ON BOARD DIAGNOSIS LOGIC
When a misfire occurs, engine speed will fluctuate (vary). If the engine speed fluctuates enough to cause the crankshaft position sensor (POS) to vary, ECM can determine that a misfire is occurring.

The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage)
On the first trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to overheating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the crankshaft position sensor (POS) signal every 200 engine revolutions, for a change.
When the misfire conditions decreases to a level that will not damage the TWC, the MIL will turn off. If another misfire conditions occurs that can damage the TWC on a second trip, the MIL will blink. When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on. If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.

P0300 - P0304:

2. Two Trip Detection Logic (Exhaust quality deterioration)
For misfire conditions that will not cause damage to the TWC (but will affect vehicle emissions), the MIL will only light when the misfire is detected on a second trip. During this condition, the ECM monitors the crankshaft position sensor (POS) signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.




DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE (Overall)

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.

TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.

With Consult
1. Turn ignition switch "ON", and select "DATA MONITOR" mode with CONSULT-II.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch "OFF" and wait at least 5 seconds.
4. Start engine again and drive at 1,500 - 3,000 rpm for at least 3 minutes.
Hold the accelerator pedal as steady as possible.

NOTE: Refer to the freeze frame data for the test driving conditions.

5. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

OR

With Generic Scan Tools
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch "OFF" and wait at least 5 seconds.
3. Start engine again and drive at 1,500 - 3,000 rpm for at least 3 minutes.
Hold the accelerator pedal as steady as possible.

NOTE: Refer to the freeze frame data for the test driving conditions.

4. Select "MODE 7" with GST.
5. If 1st trip DTC is detected, go to "Diagnostic Procedure" below.

Part 1:

Part 2:

DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION

Part 3:

Ignition wires
1. Inspect wires for cracks, damage, burned terminals and for improper fit.
2. Measure the resistance of wires to their distributor cap terminal. Move each wire while testing to check for intermittent breaks.

Resistance: 13.6 - 18.4 Kohm/m (4.15 - 5.61 Kohm/ft) at 25 °C (77 °F)

If the resistance exceeds the above specification, inspect ignition wire to distributor cap connection. Clean connection or replace the ignition wire with a new one.