Signs of Bad Spark Plugs in NHTSA Records, and Quote Lines
A manufacturer bulletin filed with NHTSA on cracked spark plugs in 3.6L Pentastar engines (2020-2021 Chrysler, Dodge, Jeep and Ram models) lists an illuminated Malfunction Indicator Lamp, cylinder misfire diagnostic trouble codes and a rough running engine. These are reported conditions for specific vehicles, not a diagnosis.
Conditions described in NHTSA records.
- Malfunction Indicator Lamp illumination
Bulletin 10187706 (09-013-20 REV. A): CHRYSLER PACIFICA 2020-2021, DODGE DURANGO 2020-2021, JEEP GLADIATOR 2021 and 3 other models - Cylinder misfire diagnostic trouble codes
Bulletin 10187706 (09-013-20 REV. A): CHRYSLER PACIFICA 2020-2021, DODGE DURANGO 2020-2021, JEEP GLADIATOR 2021 and 3 other models - Rough running engine
Bulletin 10187706 (09-013-20 REV. A): CHRYSLER PACIFICA 2020-2021, DODGE DURANGO 2020-2021, JEEP GLADIATOR 2021 and 3 other models - Cracking in the ceramic portion of the sparkplug
Bulletin 10207925 (21NA289): CHEVROLET EQUINOX 2021, GMC TERRAIN 2021 - Incorrect spark plugs that could come apart over time and cause engine damage
Recall 21V124000: certain 2020 CLA45 AMG vehicles - Engine damage may result in an engine stall, increasing the risk of a crash
Recall 21V124000: certain 2020 CLA45 AMG vehicles
What NHTSA records show.
- 1 light-vehicle recall received since January 1, 2016 names this part in its title; it does not carry the NHTSA “Do Not Drive” advisory.
- 9 manufacturer communications (revisions and joint re-filings counted once) received by NHTSA in 2020-2024 (light vehicles only) are filed under this part.
- Models named most often in these communications, model years 2010-2023: CHEVROLET EQUINOX 2010-2022 (3 communications); GMC TERRAIN 2010-2021 (3 communications); LAND ROVER DEFENDER 2019-2023 (2 communications); LAND ROVER DISCOVERY 2016-2023 (2 communications).
- By make: CHEVROLET 3, GMC 3, BUICK 2, LAND ROVER 2.
- Recalls by manufacturer: Mercedes-Benz USA, LLC 1.
“3.6L Pentastar Upgrade Spark Plug Internal Crack […] Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, a technician may find one or more of the following Diagnostic Trouble Codes (DTCs) have been set:P0301 - Cylinder 1 Misfire. P0302 - Cylinder 2 Misfire. P0303 - Cylinder 3 Misfire. P0304 - Cylinder 4 Misfire. P0305 - Cylinder 5 Misfire. P0306 - Cylinder 6 Misfire. Customers may also comment on the following:Rough running engine.”
Checked on October 13, 2026.
Lines of a spark plug replacement quote.
| Line on the quote | In the tool |
|---|---|
| Misfire diagnosis | Listed |
| Spark plugs | Listed |
| Ignition coils, boots or plug wires | Listed |
| Intake gaskets or seals, if removed | Listed |
| Labor | Listed |
| Shop supplies / disposal fees | Listed |
| Tax written on the quote | Listed |
| Coupon, discount or credit | Listed |
| Questions to ask the shop |
|---|
| How many plugs does the quote cover, and is it every cylinder? |
| Which plug type is quoted, and does it match the manufacturer's specification? |
| Are the ignition coils being replaced, and what shows they need it? |
| Does the intake have to come off to reach the rear plugs, and are new gaskets included? |
| Is this scheduled replacement, or a repair for a misfire, and was a diagnosis done? |
Where the facts come from.
- National Highway Traffic Safety Administration (U.S. Department of Transportation) — Manufacturer communications received by NHTSA 2020-2024 (TSBS_RECEIVED_2020-2024, flat file) (opens an external site)
- National Highway Traffic Safety Administration (U.S. Department of Transportation) — Recalls, NHTSA via U.S. DOT open data (Socrata 6axg-epim) (opens an external site)
What this page cannot tell you.
- RepairWorth does not inspect vehicles, identify a fault from symptoms or recommend a repair.
- NHTSA counts cover light vehicles (cars, SUVs, light pickups and vans) filed with the agency; they are not failure rates.
Content status: Editorial review: AI-assisted, each condition and count checked against the NHTSA records cited, then four adverse QA passes, October 15, 2026; not a diagnosis.