Hi everyone,
I’m currently in a battle with my local Mazda dealership and I’m looking for technical advice or similar experiences.
The Car: 2020 Mazda 3 (Skyactiv).
The Problem: Recently, my car started displaying a fake ambient temperature of -30°C (-22°F) on the dashboard when it was actually 4°C (39°F) outside. Shortly after, the Check Engine light came on and my transmission completely overheated and failed.
The Technical Link: After some research, I found that the PCM (Powertrain Control Module) uses the ambient temperature to manage the Coolant Control Valve (CCV) (covered under SSPD8) and the Active Air Shutters (flaps) at the front.
Because the car "thought" it was freezing outside (-30°C), it kept the shutters closed and the CCV blocked the coolant flow to the transmission cooler to "preserve heat." This caused the transmission oil to cook, leading to total failure.
The Dealer's Negligence:
The worst part? I had previously brought the car in for a known issue with the Active Air Shutters (TSB 01-016/20). The dealer noted in my file that the flaps were faulty and even wrote "DO NOT DRIVE" on the report, but they never performed the repair and let me leave with the car anyway without a formal warning.
Current Situation:
Mazda is willing to pay for the transmission (parts), but the dealer is trying to make me pay for the labor.
I have the TSB 07-003/24 which confirms that the 2020 ambient temp sensors have a "poor soldering" manufacturing defect. I argue that this is a domino effect:
- Defective Sensor (TSB 07-003/24) + Faulty Shutters (Dealer negligence)
- Caused the Valve (SSPD8) to stop cooling the transmission.
- Result: Dead Transmission.
Questions:
- Has anyone else had their transmission fail because of a faulty ambient temp sensor or stuck shutters?
- Does anyone have more technical documentation showing the link between the Ambient Temp Sensor and the Transmission cooling logic?
- Since this is a chain reaction caused by documented manufacturing defects (TSBs) and dealer negligence, shouldn't labor be 100% covered?
Thanks for your help!