The last few years have seen an explosion in automotive technology with cars adding new safety systems including blind spot sensors and automatic braking as well as advanced infotainment systems that act as WiFi hotspots and convenience features like automatic doors. Today, scanning the onboard computers isn’t just done by mechanics diagnosing engine problems, it’s a vital tool for repairing vehicles after accidents and making sure these new features work as intended. Even doing something as simple as disconnecting the battery can require the recalibration of multiple systems throughout the vehicle, which makes scanning a crucial step in each stage of the repair process.
How Complex are Modern Cars?
In the past, a car might have an ECU to control the engine, a TCU to control the transmission, and one or two more computers to control functions like anti-lock brakes or airbags. Late model cars also have advanced infotainment systems that can handle music, navigation and web-based apps, convenience features including smartphone integration and automatic doors, and safety systems including automatic braking and crash detection.
On average, the computers in a new car run a total of around 100 million lines of code, or about twice as much software as a complete installation of Windows 10. These computers also need to coordinate their actions using a Controller Area Network (CAN) bus, which is similar to the LAN networks used in offices to connect desktop computers. Getting all of those functions to work right requires monitoring and diagnosis of this complex system when making body repairs.
Making Modern Vehicles Safe
Ensuring repairs are done correctly on modern vehicle electronics has become an industry-wide effort with vehicle manufacturers, aftermarket manufacturers, industry organizations, insurance agencies and repair shops coming together to share information. The result is a system that affects everyone from large companies to individual technicians.
Groups made up of experts from all parts of the industry establish best practices for repairs, ensuring vehicles are returned to the same function as they were pre-collision.
Vehicle manufacturers work with tool companies to create scanners that will work with the car’s onboard computers and make repair information available to shops so they can diagnose and repair everything on the vehicle.
To keep up with these changes, training programs and certifications are updated constantly so that technicians can get the information they need to make these repairs.
Scanning Through the Repair Process
Using scan tools can reveal information that isn’t obvious during a visual inspection. The error codes and test information comes into play in three ways when making repairs:
Damage to sensors and wiring is often hidden: even if a body panel looks fine, the underlying structure may have flexed enough to damage wiring connections and change the position of sensors, throwing off readings.
Repairs can change the position of sensors. This movement can be caused by something major like a dent repair, or a minor detail, such as a slight change in panel gaps when fitting new parts.
A car goes through gradual changes as it ages due to wear and tear, and the electronic systems need to adjust to that wear to work correctly, whether it’s compensating for variations in a sensor’s output or giving a servo motor a little extra power to overcome friction. When the battery is disconnected, the computers lose the information on these adjustments, requiring recalibration to work correctly. In the past, these calibrations were simple: the car may just need to be driven a while to relearn how to control the idle and when to shift the transmission. Now this includes functions like knowing the seat position to deploy the airbags correctly and at what point an increase in electrical load indicates something is blocking the movement of an automatically-opening door.
To ensure these systems are repaired correctly, scanning takes place at least three times:
• Pre-Scan/Health Scan – Before repairs begin, a scan tool is used to find any errors stored in the system and capture diagnostic codes. This lets the technicians find faults quickly so they can be addressed. If the electrical system is damaged to the point that it can’t be switched on, this scan happens as soon as the system has been repaired to a point that it can function.
• Post-Scan – The computers are scanned to ensure any issues found during the pre-scan have been corrected and no new issues have cropped up during repairs. Some codes may only appear when certain conditions are met, such as reaching a certain number of start cycles or miles driven.
• Post-Repair Calibration/Initialization (PRC/I) – Any system affected by the repair is checked and calibrated to fall within manufacturer’s specifications.
The Expertise You Need to Get Your Car Working Again
Merton Auto Body is an I-CAR Gold Class shop and our technicians are ASE certified, which means we have the latest in tools and techniques to make sure your car’s electronics are fully functional when your vehicle leaves the shop.