Publication date: 2022-11-17
Reference number: MT-021/17
Supersedes refnos: MT-005/22

CHECK ENGINE LIGHT ON WITH DTC P0171

TECHNICAL SERVICE BULLETIN

Reference Number(s): MT-005/22, Date of Issue: November 17, 2022

MAZDA:

2012-2013 Mazda3 (SKYACTIV Models); 2014-2023 Mazda3; 2014-2021 Mazda6; 2016-2019 CX-3; 2013-2023 CX-5; 2016-CX-9; 2022-2023 CX-30; 2023 CX-50; 2016-2022 MX-5

Superceded Bulletin(s): MT-021/17, Date of Issue: 12/05/2017

BULLETIN NOTES

This M-Tip supersedes the previously issued service M-Tip(s) listed below. The changes are below.

PREVIOUSLY ISSUED SERVICE M-TIP LIST

Previous M-Tips:	Date(s) Issued:
MT-021/17	12/05/2017

APPLICABLE MODEL(S)/VINS

2012-2013 Mazda3 (SKYACTIV Models)	2014-2023 Mazda3	2014-2021 Mazda6	2016-2019 CX-3
2013-2023 CX-5	2016-CX-9	2022-2023 CX-30	2023 CX-50
2016-2022 MX-5

DESCRIPTION

Some vehicles may experience the Check Engine Light ON with DTC P0171 (Fuel Trim too Lean) and possibly DTCs P030X (Misfire).

Vehicles having this concern should use the following Inspection/Repair procedure.

REPAIR PROCEDURE

Inspection Procedure

Inspect the airbox/air filter for proper fitment and repair if necessary.
Inspect the MAF for correct operation according to the instructions on MGSS and repair if necessary.
Inspect the A/F sensor for correct operation according to the instructions on MGSS and repair if necessary.
Inspect the Fuel Trims during normal engine idle condition.
- If fuel trims are normal after performing steps 1- 3, repair is complete.
- If fuel trims remain abnormal, continue to Repair Procedure.

NOTE: P0171 will set while the engine is idling or the vehicle is driven and the fuel feedback correction amount reaches the upper limit (25 % or more) for 20 s or more.

Repair Procedure

Replace the fuel injectors
Verify fuel trims have been corrected.
- If the Check Engine light turns on again, follow the Repair Procedure in the WSM.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Check Engine Light On With DTC P0171 (MT-021/17)