2020 Mazda MAZDA3 Technical Service Bulletins

726 technical service bulletins (TSBs) are on record for the 2020 Mazda MAZDA3. TSBs are notes manufacturers send to dealers about repair procedures for issues seen in the field. They are not recalls and do not by themselves mean a vehicle has a fault.

• 10170821Jan 2, 2020Equipment, Electrical system. When performing Recall 4219L, make sure to connect a battery charger as stated in the Recall. If there are any issues, contact Hotline for assistance.
• 10169505Dec 20, 2019Wheels. Some vehicles may exhibit corrosion of the wheel nuts. This is caused by torsional stress concentrating on the tip of the wheel nut because of the thin and long shape of the nut, which damages the coating and causes the corrosion. To correct this issue, the width across the flats of the wheel nuts have been changed from 17mm to 21mm.
• 10169540Dec 19, 2019Equipment, Engine cooling. If an engine assembly is replaced after a catastrophic internal mechanical failure, clean the intake manifold internally before installing a replacement engine assembly. If the intake manifold is not cleaned properly, the replacement engine may fail prematurely. Metallic debris from the old engine (with catastrophic internal mechanical failure) may rest inside the intake manifold.
• 10169513Dec 18, 2019Other or unknown, Transmission and drivetrain. WARRANTY GUIDELINES FOR RETURNED TRANSMISSION CORES. Be advised that the Mazda Remanufactured Transmission Center (MRTC) has found that up to 30% of the returned transmission cores either included the wrong transmission oil cooler, or the oil cooler was missing altogether. IMPORTANT NOTE: ALWAYS REMEMBER TO INCLUDE THE ORIGINAL OIL COOLER WITH THE RETURNED TRANSMISSION CORE!
• 10169539Dec 17, 2019Equipment. A musty/mildew type odor may come from the vents when the air conditioning (A/C) system is operating. It is most noticeable when the A/C is first turned ON. This odor is the result of mold growth in the A/C evaporator/cooling unit which is caused by condensation, dust, and pollen within the cooling unit. This condition is usually worse during high humidity conditions. “Mazda Air Cooling Coil Coating” is…
• 10169535Dec 17, 2019Exterior lighting, Equipment, Visibility (wipers, defrost, mirrors). Some customers may complain about an instrument cluster warning message "Auto Light System Malfunction. Turn On/Off Lights Manually". DTC B10AD:09 (Humidity sensor/solar radiation sensor/auto light sensor/rain sensor malfunction) may also be stored with the exterior light warning indicator light ON. This is caused by the rain sensor detecting a temperature higher than the operation range and temporarily stopping…
• 10169543Dec 13, 2019Equipment, Other or unknown, Visibility (wipers, defrost, mirrors). Accessory instructions can be found in the Accessory eCatalog. https://ecatalog.trademotion.com/. Audio/Electrical, Exterior, Interior: - Mazda Mobile Start (MMS) - Remote Engine Start - Wireless Charging Pad - Mirror - Navigation - Rear Parking Sensors - Rear Seat Entertainment - Smartphone Screen Mirroring - Bumper Trim/Guards - Door Mirror Caps - Fog Lights - Moonroof Wind Deflector - Roof Rack - Side Window…
• 10169537Dec 13, 2019Equipment, Engine cooling. There is a concern that some water pumps are being replaced that are not faulty, due to signs of a very small coolant leak from the bleed hole. This Service Bulletin is to inform you about the water pump sealing mechanism and the criteria if replacement is necessary or not.
• 10169536Dec 13, 2019Transmission and drivetrain, Engine cooling. Some customers may experience the CHECK ENGINE light ON with DTC P0012:00 (Electric variable valve timing control system: Over-retarded) stored in PCM memory. NOTE: This concern occurs only on the vehicles with PCMs manufactured by MITSUBISHI.This is caused by improper control logic of the PCM detecting a false error. To correct this issue, the PCM software has been modified. NOTE: The VVT actuator is damaged by…
• 10169507Dec 12, 2019Equipment. Customers having MAZDA CONNECT concerns should have their vehicle repaired using the following repair procedure.
• 10169509Dec 5, 2019Engine cooling, Transmission and drivetrain. GUIDE LINES AND PHOTOS TO DETERMINE IF FLUID/OIL SEEPAGE OR LEAK IS SEVERE ENOUGH TO REQUIRE WARRANTY REPAIR OR TO CLEAN AND MONITOR. Some customer's might state that they notice fluid or oil leaking/dripping on the ground when the vehicle is parked. For this concern, inspect the vehicle for any trace of a fluid or oil leak and use the following examples as a guide to determine if it is severe enough to require a…
• 10168786Nov 26, 2019Engine cooling. Some vehicles may exhibit an excessive body vibration when idling or driving after being left in extremely cold weather (-20°F or below) for a long time. This is caused by the No.1 engine mount (1) rubber hardening due to material characteristics.
• 10168142Nov 21, 2019Equipment, Forward collision avoidance. FSC dynamic aiming (mid-drive aiming) may not complete if the vehicle is driven on a road as described below:  The road lane markings are covered by snow and are not visible.  There are no road lane markings on the road surface.  The road is winding and the vehicle cannot drive straight (300 m / 984 ft or more turning radius is required). FSC dynamic aiming is completed if the following conditions…
• 10168139Nov 20, 2019Electrical system, Equipment, Engine cooling. Some customers may complain about:  Intermittent engine no start  Instrument cluster red security indicator light ON  Engine Start/Start Button Amber indicator light flashing  Battery discharge  Electrical relay buzzing noise  DTC B13D3:94 (Communication error with remote transmitter) stored.This may be caused by:  A key in a purse near a cell phone. The cell phone radio…
• 10168121Nov 8, 2019Body and structure, Equipment, Visibility (wipers, defrost, mirrors). On certain subject vehicles, it is possible that the chrome plated window moldings may be dirty or have rust spots. The subject vehicles were parked outside when Typhoon No.17 passed through Hiroshima and Hofu, Japan, and might have been exposed to misty seawater caused by a heavy wind. The sampling inspection revealed that the chrome plated window moldings of certain vehicles became rusty due to seawater mist.
• 10168074Nov 7, 2019Equipment, Electrical system, Forward collision avoidance. Some vehicles may experience M-MDS (MDARS) showing the front radar dynamic aiming is incomplete, although the procedure is completed. This is caused by faulty front radar software logic and a mass production change is planned. If the screen below is displayed after the front radar dynamic aiming is performed, check the vehicle using the following inspection procedure.
• 10168115Nov 5, 2019Electrical system, Equipment. On the 2019 Mazda3 (BP) and and all 2020 Mazda vehicles (except CX-3), the CR2032 button cell battery is required for the new type remote transmitter. If it is mistakenly replaced with the conventional CR2025 used in the previous type remote transmitter, it may cause a malfunction. Verify the button cell battery type before replacing it.
• 10166853Oct 30, 2019Equipment, Electrical system. Currently, Mazda does not have a way to cut the auxiliary keys for the new style remote transmitter as they use a different key code than the previous transmitter key. Follow the repair procedure if one or both auxiliary keys are lost:
• 10166847Oct 24, 2019Electrical system, Engine cooling. The "FORCED IGNITION ON PROCEDURE" was made available to dealers through this service alert.
• 10166846Oct 17, 2019Electrical system, Equipment. On 7th generation vehicle (2019-2020 Mazda3 (BP) and 2020 CX-30 (DM)), when the door is opened/closed with the ignition switch off, the battery current is approximately 7A, which is three times larger than previous generation models (2.5A on Mazda6 (GL)). In addition, after the door is closed, a 6A current continues for 6 minutes on 7th generation vehicles.
• 10166844Oct 2, 2019Exterior lighting. Some customers may complain about an instrument cluster warning message "Auto Light System Malfunction. Turn On/Off Lights Manually". DTC B10AD:09 (Humidity sensor/solar radiation sensor/auto light sensor/rain sensor malfunction) may also be stored with the exterior light warning indicator light ON.display. This is caused by the rain sensor detecting a temperature higher than the operation range and temporarily…
• 10166850Oct 1, 2019Equipment, Latches, locks and linkages, Electrical system. Outline of concern: On certain subject vehicles, it is possible the following concerns may happen when the connectivity service is available. 1. The hands-free capability does not work properly due to a communication error between CMU (Connectivity master unit) and the microphone. 2. The communication failure happens between the TCU (Telematics Communication Unit) and connectivity server due to improper software of…
• 10165676Sep 30, 2019Engine cooling. If an engine assembly is replaced after a catastrophic internal mechanical failure, clean the intake manifold internally before installing a replacement engine assembly. If the intake manifold is not cleaned properly, the replacement engine may fail prematurely. Metallic debris from the old engine (with catastrophic internal mechanical failure) may rest inside the intake manifold.
• 10165677Sep 25, 2019Equipment, Electrical system. Customers having MAZDA CONNECT concerns should have their vehicle repaired using the following repair procedure. NOTE: Before proceeding: Confirm that the Connectivity Master Unit (CMU) is updated to the latest software version. Go to MGSS - Infotainment - MAZDA CONNECT Updates, Confirm that the customers device is updated to the latest software version. Apple Carplay/Android Auto FAQ, go to SA-001/19.
• 10165352Sep 16, 2019Wheels, Equipment, Lane departure, Visibility (wipers, defrost, mirrors)…. 2019-2020 MAZDA3 SERVICE CAUTIONS FOR NEW AND REVISED FEATURES. The 2019-2020 Mazda3 has new and revised features that are different from previous models, and may be difficult to understand. This Service Alert provides valuable information to support potential dealer and customer concerns.
• 10186263Dec 19, 2016Electrical system, Equipment. MAZDA Mobile start (MMS) cannot communicate with vehicle

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