No. 77-21

Service
Technical Information
77/21
ENU
2870
2
Complaints Immediately or Shortly After Changing or Removing and Installing Spark Plugs:
Observe Specified Procedure (77/21)
Vehicle Type:
911 Carrera (991)/911 Carrera S (991)/911 Carrera GTS (991)
911 Carrera (992)/911 Carrera S (992)
718 Boxster (982)/718 Boxster T (982)/718 Cayman (982)/718 Cayman T (982)
Model Year:
As of 2017
Equipment:
3.0-liter petrol engines (911)
2.0-liter petrol engines (718)
Concerns:
Spark plugs
Information:
The customer complains about one or more of the following issues immediately or shortly after removing
and installing or changing spark plugs:
•
•
•
Check Engine warning light comes on
Vehicle jerking
Rough-running engine
This may be caused by incorrect installing of the spark plugs using an incorrect or worn tool. As a
result, the ceramic body will be damaged by excessive transverse forces when tightening it in the slightly
angled spark-plug recess.
The electrodes can also touch and bend when inserting them.
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Jul 15, 2021
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Service
2870
ENU
Technical Information
77/21
Damage to spark plugs
1
2
3
4
–
–
–
–
Electrode bent
Insulator tip broken
Insulator broken
Housing/connection damaged
NOTICE
Damaged, worn or incorrect tool
•
Risk of damage to spark plugs

Only use the prescribed tool and install spark plugs according to instructions in the relevant Workshop
Manual.
Action required: Use the prescribed tool when removing and installing spark plugs:
•
•
Double hexagon socket for spark plugs, a/f 14
Extension, 3/8''
Install spark plugs according to instructions in the relevant Workshop Manual.
 Workshop Manual '287020 Removing and installing spark plugs'
Jul 15, 2021
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Service
Technical Information
77/21
ENU
2870
2
Information
Damaged spark plugs as a result of incorrect installing must not be invoiced using the new vehicle
warranty or Porsche Approved Warranty (PAW) and can be re-debited as required after checking.
Important Notice: Technical Bulletins issued by Porsche Cars North America, Inc. are intended only for use by professional automotive technicians who have attended Porsche service training
courses. They are written to inform those technicians of conditions that may occur on some Porsche vehicles, or to provide information that could assist in the proper servicing of a vehicle. Porsche special
tools may be necessary in order to perform certain operations identified in these bulletins. Use of tools and procedures other than those Porsche recommends in these bulletins may be detrimental to the
safe operation of your vehicle, and may endanger the people working on it. Properly trained Porsche technicians have the equipment, tools, safety instructions, and know-how to do the job properly and
safely. Part numbers listed in these bulletins are for reference only. The work procedures updated electronically in the Porsche PIWIS diagnostic and testing device take precedence and, in the event of a
discrepancy, the work procedures in the PIWIS Tester are the ones that must be followed.
© 2021 Porsche Cars North America, Inc.
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