This is case study article based on a video on YouTube from - Car Wizard
In a small town garage, a 2013 Smart Car Pure ForTwo arrived all the way from Nebraska, highlighting a peculiar trend: mechanics’ reluctance to work on Smart Cars. Despite their compact design and Mercedes-Benz engineering, many mechanics shy away from these vehicles, likening the task to open-heart surgery. This particular car came in with three primary issues: a shaking blower motor, a check engine light, and an air conditioning system that wasn’t blowing cold air. Let’s delve into the diagnostics and solutions for each problem.
Problem 1: Shaking Blower Motor
Upon turning on the blower motor, it shook the entire dashboard, indicating a significant imbalance. The blower motor was located in the driver’s floorboard area and was simple to remove. Upon inspection, it was discovered that a blade from the blower wheel was missing. This imbalance caused the motor to shake violently, especially on higher speeds.
Solution: Replace the entire blower motor assembly. While just replacing the blower wheel might seem like a viable option, the motor’s extended operation with an imbalance likely caused wear on the bushings, making a full replacement the more reliable choice.
Problem 2: Check Engine Light
Using an Auto Maxisys MS906 diagnostic tool, the check engine light was traced to a short circuit in the outside temperature sensor (P0730 code). This was peculiar because the sensor itself had no direct connection to the engine’s performance.
Discovery: The owner had installed a General Motors 4-note horn set, typical of 1970s Cadillacs, which likely interfered with the original sensor’s wiring. Upon a closer inspection behind the front panel, it was clear that the sensor was either relocated incorrectly or the wiring was damaged during the horn installation.
Solution: Conduct a thorough inspection behind the front bumper, repair or replace the outside temperature sensor, and ensure proper wiring. This will likely resolve both the check engine light and any associated issues with the air conditioning system.
Problem 3: Air Conditioning System
The AC was not blowing cold air, a critical issue during warm seasons. Upon checking, it was found that the refrigerant level was slightly low but not enough to cause a complete failure.
Connection to Problem 2: The air conditioning system relies on the outside temperature sensor to function correctly. With the sensor shorted or damaged, the system couldn’t regulate the AC effectively.
Solution: Along with fixing the temperature sensor, recharge the refrigerant to its proper level. This combined approach will restore the air conditioning functionality.
Additional Insights
The 2013 Smart Car Pure ForTwo, like other Smart Cars, has its engine located in the rear, under the floor carpet, making it unconventional compared to typical front-engine vehicles. Despite being engineered by Mercedes-Benz (Daimler AG), its design and compact size often deter mechanics used to more traditional setups.
Final Thoughts
Smart Cars are practical, especially in urban environments where their size and fuel efficiency shine. However, their unique design can be daunting for mechanics unfamiliar with their layout. This case from Nebraska underscores the importance of specialized knowledge and adaptability in automotive repair. By addressing the blower motor, temperature sensor, and refrigerant levels, this Smart Car is well on its way back to optimal performance, proving that with the right expertise, even the quirkiest cars can be easily maintained.