DTC P0301-P0304 (LPL or LPV)
Diagnostic Instructions
DTC Descriptors
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 - intake 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. DTCs
P0301 00 - P0304 00 correspond to cylinders 1-4. If the ECM is able
to determine that a specific cylinder that is misfiring, the DTC
for that cylinder will set.
Conditions for Running the DTC
• |
The engine speed is between
600-6 528 RPM. |
• |
The ignition voltage is
between 11-18 V. |
• |
The engine coolant temperature
(ECT) sensor 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 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 P0301 00, P0302 00, P0303 00 and P0304 00 are Type A (MIL
flashing) or Type B DTCs.
Conditions for Clearing the DTC
DTCs 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 tire 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
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
EN 36012-A Ignition System Diagnostic
Harness
For equivalent regional tools, refer to
Special Tools .
Circuit/System Verification
1. |
Engine running at the normal
operating temperature, verify there is no abnormal engine
noise. |
|
Note: A misfire may
only occur when the engine is under a load. An engine load may be
necessary to verify the condition.
|
2. |
Observe the scan tool Misfire
Current Counter parameters. The Misfire Current Counters should not
be incrementing. |
3. |
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
1. |
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. |
2. |
Ignition OFF, disconnect the
harness connector at the appropriate Q17 Fuel Injector.
|
3. |
Connect a test lamp between
the control circuit terminal 2 and the ignition voltage circuit
terminal 1. |
4. |
Engine idling, the test lamp
should flash. |
5. |
If all conditions test normal,
test or inspect for the following: |
Repair Instructions
Fuel Injector Removal
Repair Verification
1. |
Clear the DTCs with a scan
tool |
2. |
Turn OFF the ignition for 60
s. |
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. |
5. |
If the DTC fails this
ignition, a misfire still exists. |
|