NHTSA service bulletin

NHTSA Service Bulletin 10186694: 2018, 2019 Mazda Cx-9

Official manufacturer communication context for 2018, 2019 Mazda Cx-9, with affected products, buyer checks and links into Carchieve recall, problem and VIN research.

NHTSA service bulletin 10186694 summary graphic for 2018, 2019 Mazda Cx-9
10186694NHTSA document ID
Manufacturer communicationcommunication type
2affected product rows
90/100quality score

Reviewed June 2026 from NHTSA manufacturer communication and service bulletin records. Carchieve is independent and not affiliated with any vehicle manufacturer or government agency.

Quick answer

Some vehicles may exhibit an occasional rough idle accompanied with DTC P0300:00 (Random misfire) due to the following: 1. While closing the EGR valve, carbon deposit etc. pinched at the valve seat prevents the valve from closing completely. 2. The closed position of the EGR valve is learned improperly as it is not equipped with a position sensor. 3. While idling, the EGR gas improperly mixes in fresh air through the EGR valve that is not closed properly. 4. Misfire occurs. To eliminate this concern, the control software of the PCM has been modified to force the learning of the closed position of the EGR valve when a misfire is detected at idle

What this bulletin may mean before buying

Treat this as service research, not a verdict on one car. Before you buy, compare this communication with official recall campaigns, model-level owner complaint patterns, and the exact vehicle’s VIN-decoded specifications. A bulletin can help you ask a seller or dealer sharper questions about software updates, known repairs, warranty extensions and service history.

Affected products listed in this communication

MakeModelModel yearsBuyer note
MazdaCx-92018Ask for service records and run the exact VIN before purchase.
MazdaMazda62018, 2019Ask for service records and run the exact VIN before purchase.

Buyer checklist

  1. Run the 17-character VIN and confirm the year, make, model, engine and equipment match the listing.
  2. Check recall campaign pages for safety actions that may require dealer repair.
  3. Compare this bulletin with common problem pages for the same model and component area.
  4. Ask the seller or dealer whether the bulletin procedure, update or inspection has already been completed.
  5. Use the used-car buying checklist and get an independent inspection.

Frequently asked questions

What is NHTSA service bulletin 10186694?

Some vehicles may exhibit an occasional rough idle accompanied with DTC P0300:00 (Random misfire) due to the following: 1. While closing the EGR valve, carbon deposit etc. pinched at the valve seat prevents the valve from closing completely. 2. The closed position of the EGR valve is learned improperly as it is not equipped with a position sensor. 3. While idling, the EGR gas improperly mixes in fresh air through.

Is a service bulletin the same as a recall?

No. A recall is a safety campaign with a required remedy for affected VINs. A service bulletin or manufacturer communication usually describes diagnostic, repair, software, warranty or service information.

How should a used-car buyer use this bulletin?

Use it as a research signal. Compare it with recalls, owner complaints, service records, a VIN report and an independent inspection before buying.

Check the exact VIN before you buy

Model-level pages show public safety patterns. A full VIN report helps confirm the exact vehicle, decoded specs, recall applicability and buyer checks.

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