NHTSA ID Number: 11028515
Manufacturer Communication Number: A26-001
TSB/Document Date: 2026-02-06
Summary
Service Bulletin - The piston ring function deteriorates due to ring low wear toughness and sticking from sludge. Oil adheres to the spark plug leading to carbon fouling and misfire. This can set DTCs P0301 No. 1 cylinder misfire detected, P0302 No. 2 cylinder misfire detected, P0303 No. 3 cylinder misfire detected, P0304 No. 4 cylinder misfire detected, and cause the MIL to come on.
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TSB/Document ID: A26-001
Replacement Service Bulletin Number:
MFR Communication Date: 2026-02-01
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: ENGINE
MFR Component System:
MFR Component Subsystem:
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Service Bulletin
26-001
February 1, 2026
Version 1
Warranty Extension: 2013–17 Odyssey MIL Comes on with DTCs P0301
Thru P0304
APPLIES TO
Year
Model
Trim Level
2013–17
Odyssey
ALL
VIN Range
Check the iN VIN status for eligibility.
BACKGROUND
American Honda is extending the powertrain warranty to cover repairs related to engine misfire (that triggers DTCs P0301
thru P0304) to 10 years from the original date of purchase or 150,000 miles, whichever comes first.
The piston ring function deteriorates due to ring wear and sticking from sludge. Oil from the crankcase adheres to the spark
plug leading to carbon fouling and misfire. This can set DTCs P0301 No. 1 cylinder misfire detected, P0302 No. 2 cylinder
misfire detected, P0303 No. 3 cylinder misfire detected, P0304 No. 4 cylinder misfire detected, and cause the MIL to
come on.
CUSTOMER NOTIFICATION
Owners of affected vehicles will be sent a notification of this campaign.
Do an iN VIN status inquiry to make sure the vehicle is shown as eligible.
CORRECTIVE ACTION
Complete the DIAGNOSIS PROCEDURE and, if necessary, update the PCM software, replace affected spark plugs then
clean pistons and replace the piston rings. If cylinder inspection fails, perform engine block replacement, replace affected
spark plugs, and update the PCM software.
Additionally, the following videos are available to help with this bulletin:
•
Tech2Tech: "How to Clean Piston Ring Grooves”
•
Tech2Tech: “Let's Talk Piston Ring Compressors”
•
Tech2Tech: “Cylinder Wall Inspection Tool”
CUSTOMER INFORMATION: The information in this bulletin is intended for use only by skilled technicians who have the proper tools, equipment,
and training to correctly and safely maintain your vehicle. These procedures should not be attempted by “do-it-yourselfers,” and you should not
assume this bulletin applies to your vehicle, or that your vehicle has the condition described. To determine whether this information applies, contact
an authorized Honda automobile dealer.
© 2026 American Honda Motor Co., Inc. – All Rights Reserved
Page 1 of 65
WARRANTY CLAIM INFORMATION
FLAT RATE NOTE: The procedure in this bulletin is different than the service manual. This procedure does not require the
complete removal of the power steering pump, catalytic converter(s), engine and transmission, or the crankshaft. As a
result, the operation number is unique and the FRT is reduced (Repair Procedure A)
IMPORTANT: A printed copy of the completed ALL DTC check is required to be attached to the claim submission. If the
ALL DTC Check printout is not attached to the claim, the claim will not be processed or could be subject to debit.
DTC P0301, P0302, or P0303
No scratching or scoring detected
Operation
Number
Description
Flat Rate
Time
DTC P0301, P0302 or
P0303: Inspect spark
plug(s)
0.3hr
A
Repair procedure A:
Remove cylinder head,
inspect cylinders, clean
pistons 1-3, replace piston
rings 1-3 and replace
spark plugs 1-4 (includes
idle learn)
8.3hr
C
Update the PCM software
(includes DTC clear)
0.1hr
1115A9
Defect
Code
Symptom
Template ID
Code
Failed Part Number
6V500
NLV00
A26001A
13021-5G0-A01
Defect
Code
Symptom
Code
Template ID
Failed Part Number
6V500
NLV00
A26001B
13021-5G0-A01
Scratching or scoring detected
Operation
Number
Description
Flat Rate
Time
1115A9
DTC P0301, P0302 or
P0303: Inspect spark
plug(s)
0.3hr
B
Repair procedure B:
Remove cylinder head,
inspect cylinders, replace
short block and replace
spark plugs 1-4 (includes
Idle learn & align)
11.1
C
Update the PCM software
(includes DTC clear)
0.1hr
Page 2 of 65
DTC P0304
No scratching or scoring detected
Operation
Number
Description
Flat Rate
Time
1115B0
DTC P0304: Inspect spark
plug(s)
0.3hr
A
Repair procedure A:
Remove cylinder heads,
inspect cylinders, clean
pistons 1-4, replace piston
rings 1-4 and replace
spark plugs 1-4 (includes
idle learn)
9.1hr
C
Update the PCM software
(includes DTC clear)
0.1hr
Defect
Code
Symptom
Code
Template ID
Failed Part Number
6V500
NLV00
A26001C
13021-5G0-A01
Defect
Code
Symptom
Code
Template ID
Failed Part Number
6V500
NLV00
A26001D
13021-5G0-A01
Scratching or scoring detected
Operation
Number
Description
Flat Rate
Time
1115B0
DTC P0304: Inspect spark
plug(s)
0.3hr
B
Repair procedure B:
Remove cylinder heads,
inspect cylinders, replace
short block and replace
spark plugs 1-4 (includes
Idle learn & align)
11.1hr
C
Update the PCM software
(includes DTC clear)
0.1hr
Page 3 of 65
PARTS INFORMATION
NOTE: Use the parts list for Repair Procedure A OR Repair Procedure B, based on the repair direction.
Repair Procedure A: Piston Cleaning and Ring Replacement
Part Name
Part Number
Quantity
Cyl 1-3
Cyl 1-4
Cyl. Gasket (Fr)
12251-R70-A01
-
1
Cyl. Gasket (Rr)
12261-R70-A01
1
1
94109-14000
1
1
EGR Pipe Gasket A
18716-R70-A01
1
1
EGR Pipe Gasket B
18719-R70-A01
1
1
Ex. Chamber Gasket
18115-R70-A01 or 181155G0-A01
1
2
Ex. Pipe Gasket
18212-SA7-003
2
2
Head Gasket Fr. (Valve Cover)
12030-R70-A00
-
1
Head Gasket Rr. (Valve Cover)
12050-R70-A00
1
1
In. Manifold Gasket (Intake Top Cover)
17146-R70-A01
1
1
In. Manifold Gasket (In. Manifold to Base)
17105-RCJ-A01
1
1
15400-PLM-A02
1
1
O-ring (7.47 mm x 3.6 mm)
91301-PLC-000
2
2
O-ring (31.2 mm x 4.1 mm)
91314-PH7-003
2
2
Piston Ring Set
13011-RV0-305
3
4
Pre-chamber Gasket
18393-SDB-A00
1
1
Self-locking Nut (8 mm)
90212-RCA-A01
4
8
Self-locking Nut (10 mm)
90212–SA5-003
9
9
12290-R71-L01
4
4
Strainer O-ring
15221-RYE-A01
1
1
Bolt, Flange (Side Engine Mount Bolts)
90164-SHJ-A00
2
2
Bolt, Flange (12 x 115) (Side Engine Mount
Bolt)
90161-SZA-A00
1
1
Drain Washer (14 mm)
Page 4 of 65
Repair Procedure A: Piston Cleaning and Ring Replacement – cont.
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