DTC P0300-P0304 - LDE
Diagnostic Instructions
DTC Descriptors
DTC P0300 00: Engine Misfire Detected
DTC P0301 00: Cylinder 1 Misfire
Detected
DTC P0302 00: Cylinder 2 Misfire
Detected
DTC P0303 00: Cylinder 3 Misfire
Detected
DTC P0304 00: Cylinder 4 Misfire
Detected
Circuit/System Description
The engine control module (ECM) uses information from the
crankshaft position sensor in order to determine when an engine
misfire is occurring and uses information from the camshaft
position sensor inlet and camshaft position sensor exhaust sensors
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 emission levels to exceed
mandated standards, DTC P0300 00 sets. Under certain driving
conditions, a misfire rate can be high enough to cause the 3-way
catalyst 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 00 is set.
DTCs P0301 00-P0304 00 correspond to cylinders 1-4.
If the ECM is able to determine that a specific cylinder is
misfiring, the DTC for that cylinder will set.
Conditions for Running the DTC
• |
DTCs P0010 00, P0011 00, P0013 00,
P0014 00, P0016 00, P0017 00, P0101 00,
P0102 00, P0103 00, P0112 00, P0113 00,
P0117 00, P0118 00, P0121 00, P0122 00,
P0123 00, P0222 00, P0223 00, P0315 00,
P0335 00, P0336 00, P0502 00, P0651 00, and
P2135 00 are not set. |
• |
The engine speed is between
600-6 528 RPM. |
• |
The ignition voltage is between 11-18 V. |
• |
The engine coolant temperature (ECT) is
between -7 to +125°C (+19 to +257°F). |
• |
The A/C compressor clutch is not changing
states. |
• |
The fuel tank level is greater than 15%. |
• |
The ECM is not in fuel cut-off or deceleration
fuel cut-off mode. |
• |
The ECM is not receiving a rough road signal. |
• |
The throttle angle is steady within 5%. |
• |
The throttle angle is greater than 3% when the
vehicle speed is greater than 5 km/h (3 mph). |
• |
The transmission is not changing gears. |
• |
The antilock brake system (ABS) and the
traction control system, if equipped, is not active. |
• |
DTCs P0300 00, P0301 00,
P0302 00, P0303 00, and P0304 00 run continuously
when the above conditions are met. |
Conditions for Setting the DTC
The ECM is detecting a crankshaft rotation speed variation
indicating a misfire sufficient to cause emission or catalyst
damaging levels to exceed mandated standards.
Action Taken When the DTC Sets
DTCs P0300 00, P0301 00, P0302 00,
P0303 00 and P0304 00 are Type A (MIL flashing) or
Type B DTCs.
Conditions for Clearing the DTC
DTCs P0300 00, P0301 00, P0302 00,
P0303 00 and P0304 00 are Type A (MIL flashing) or
Type B DTCs.
Diagnostic Aids
• |
A misfire may only occur when the engine is under
a load or when the engine is cold. |
• |
A misfire DTC may be caused by an excessive
vibration from sources other than the engine. Inspect for the
following possible sources: |
- |
A tyre or wheel that is out of round or out of
balance |
- |
Variable thickness brake rotors |
- |
Certain rough road conditions |
- |
A damaged accessory drive component or belt |
- |
A damaged reluctor wheel |
• |
High resistance in the circuits of the injectors
may set a misfire DTC without setting an injector DTC. Test the
injector circuits of the affected cylinder(s) for a high resistance
if you suspect a condition. |
• |
The MIL indicator flashes when there is an engine
misfire. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
• |
EL 26792 HEI Spark Tester |
• |
EN 36012-A Ignition System
Diagnostic Harness |
For equivalent regional tools, refer to
Special Tools .
Circuit/System Verification
- Engine running at the normal operating temperature,
verify there is no abnormal engine noise.
- Observe the DTC information with a scan tool. Verify
that DTC P0201 00, P0202 00, P0203 00,
P0204 00, P0315 00, P0335 00, P0336 00,
P0351 00, P0352 00, P0353 00, or P0354 00 are
not set.
Note: A misfire may only occur
when the engine is under a load. An engine load may be necessary to
verify the condition.
- Observe the scan tool Misfire Current Counter
parameters. The Misfire Current Counters should not be
incrementing.
- Operate the vehicle within the conditions for running
the DTC to verify the DTC does not reset. You may also operate the
vehicle within the conditions that you observed from the freeze
frame/failure records data.
Circuit/System Testing
- Verify that the following conditions do not
exist:
• |
Vacuum hose splits, kinks, and incorrect
connections |
⇒ |
If you find any of the above conditions, repair as
necessary. |
- Ignition OFF, disconnect the harness connector at the
appropriate Q17 Fuel Injector.
- Connect a test lamp between the control circuit
terminal B (1.6L) or terminal 2 (1.8L) and the ignition
voltage circuit terminal A (1.6L) or terminal 1
(1.8L).
- Engine idling, the test lamp should flash.
- Ignition OFF, connect the Q17 Fuel Injector
connector. Remove the K35 Ignition Coil Module.
- Inspect the ignition coil spark plug boots for the
following conditions:
⇒ |
If you find any of the above conditions, repair as
necessary. |
- Connect the harness connector to the ignition coil
assembly.
Note: It may be necessary to
secure the EN 36012-A Ignition System Diagnostic
Harness to the spark plug boots with electrical tape.
- Install the EN 36012-A Ignition System
Diagnostic Harness to the spark plug boots.
- Install the EL 26792 HEI Spark Tester
between the spark plug boot of the misfiring cylinder and
ground.
- Connect the remaining wires to the appropriate
cylinders.
Note: An erratic or weak spark
is considered a no spark condition.
- Attempt to start the engine and observe the
EL 26792 HEI Spark Tester. The spark tester should
spark.
- Ignition OFF, remove the spark plug from the misfiring
cylinder. Verify the following conditions do not exist with the
spark plug:
• |
Cracked, worn, incorrectly gapped |
⇒ |
If there is a condition with the spark plug,
replace the spark plug. |
- Exchange the suspected spark plug with another
cylinder that is operating correctly.
- Engine running, observe the scan tool Misfire Current
Counters. The misfire should not follow the spark plug
exchange.
⇒ |
If the misfire follows the spark plug, replace the
spark plug. |
- If all conditions test normal, test or inspect for the
following:
Repair Instructions
Repair Verification
- If the customer concern was a flashing MIL, operate
the vehicle within the conditions for running DTC P0420 00.
Refer to
DTC P0420 .
- Clear the DTCs with a scan tool.
- Turn OFF the ignition for 60 s.
- Start the engine.
- 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.
- If the DTC fails this ignition, a misfire still
exists.
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