Ignition System - MIL ON/DTC's P0300-P0312 Stored
28 10 01March 31, 2010
2023121
Vehicle Information
Condition
MIL ON, Misfire DTCs P0300-0312 Stored after performing Technical Bulletin 2021320 or 28F3/P1 Campaign
Note:
Due to multiple causes for engine misfire, ensure all campaigns and applicable TB's have been performed and/or addressed.
Repeat repairs must be carefully addressed to identify the root cause of the concern. Utilize proper diagnosis steps to ensure that the vehicle is repaired properly and that the concern has been identified, repaired and
verified.
Symptoms:
^ MIL ON.
^ Rough idle.
^ The MIL is flashing or constantly illuminated.
^ One or more of the following DTCs are stored:
^ DTC P0300 (Random/Multiple Cylinder Misfire Detected).
^ DTC P0301 P0312 (Cyl.1 Misfire Detected - Cyl.12 Misfire Detected).
^ Engine may have reduced performance without significant loss of power or stalling.
Technical Background
Production Solution
Vehicles are out of production.
Service
Obtain information from the customer
To repair the vehicle correctly, obtain as much information as possible from the customer about the symptoms of the condition and when it occurred.
^ In what situation (turning, etc.) does the condition occur?
^ Under what environmental conditions (road conditions, weather, temperature, start conditions, etc.) does the condition occur?
^ What is the operating situation of the vehicle (activated electrical equipment, gear selection, etc.) when the condition occurs?
^ Can the complaint be reproduced?
Workshop procedure
1. Read out the data memory of all engine control modules, and note the environmental conditions on the DTC log.
a. If there are other entries in addition to combustion misfires, address the other entries before addressing the cylinder misfires.
b. If DTC P0301 P0312 (Cyl.1 Misfire Detected - Cyl.12 Misfire Detected) is accompanied by P1250 (Fuel level too low), it is likely the faults occurred due to a low fuel level and not a malfunction of the coils.
c. Review all applicable TBs related to cylinder misfires and ECM software improvements before diagnosing the misfire condition. For example, if data shows that a DTC was set during cold start, search ElsaWeb for TBs related to cold start misfires.
2. Try to duplicate customer complaint based on the environmental conditions at the time the DTC was set. The freeze data gives important indicators for the traceability of the complaint, in particular if it occurs sporadically or at cold start.
3. Review the vehicle repair history for previous misfire or maintenance service that could be related to the current complaint.
4. Observe the requirements of Guided Fault Finding. Perform Guided Fault Finding in full according to the proposed sequence (test plan). Do not skip any steps.
5. Complete Guided Fault Finding correctly and set the readiness code.
Tip:
This is important to ensure that no subsequent faults occur due to the misfire.
6. In the case of single cylinder misfires:
a. Before replacing components, determine whether the complaint migrates to the other cylinders after exchanging the coils. If necessary, perform a test drive to ascertain this.
b. If the misfire migrates to the cylinder the coil was moved to, replace only the affected coil.
7. Verify repair under the same environmental conditions (e.g.: engine speed, engine load value, vehicle speed, coolant temperature, intake air temperature, ambient air pressure, voltage at terminal 30, etc.) as noted on the DTC log.
Warranty
This Technical Bulletin is informational only and not applicable to any Volkswagen warranty.
Required Parts and Tools
None
Additional Information
All part and service references provided in this Technical Bulletin are subject to change and/or removal. Always check with your Parts Dept. and Repair Manuals for the latest information.