ADAS Calibrations: Two Diagnostic Trouble Code (DTC) Myths Debunked
All OE manufacturer repair procedures require vehicles to be scanned and re-scanned before and after the repairs are completed. Many auto repair shops and collision shops will utilize a diagnostic scan tool to make sure a vehicle they repair leaves their shop with no diagnostic trouble codes (commonly known as DTC’s). These are codes and/or messages describing an issue across a certain module, system, or network in the vehicle. Typically, a clean diagnostic scan means a job well done and the repair shop can have clarity in knowing that the vehicle has no issues.
Not so fast…unfortunately that isn’t always the case, especially in Advanced Driver-Assistance Systems (ADAS). As perplexing as it may seem, ADAS features are interconnected with many other modules or systems throughout the vehicle's “network”. Additionally, a clean diagnostic scan, a scan that has no DTC’s, also does not mean that the vehicle is ready to be returned to the customer if it has ADAS functionalities in it.
Below we want to highlight two various myths we’ve been able to debunk related to DTCs and the connection they have with ADAS systems and the lessons we learned from real life experiences at our shop.
"I did a post-scan or diagnostic scan on the vehicle, there aren’t any DTC’s, this vehicle is ready to be returned to its pre-loss condition to the customer."
False! When it comes to ADAS features and the systems that are run through the ADAS modules themselves, they may be out of alignment, upside down, or just off, and a DTC may never show. Here at Crown Collision Solutions, we have seen that occur a few times in some vehicles that body shops have rightfully brought to our attention and our service.
One specific case we found this in was with a 2019 Jeep Grand Cherokee that was equipped with a Blind-Spot Monitor (BSM) system. For those that may not know, the Blind-Spot Monitor system notifies the driver when there is a vehicle in your blind spot and will alert you when you turn your directional (blinker here in Massachusetts lol) on typically via an audible or visual alert. The modules that identify a vehicle or obstruction in your vehicle's blind spot are most likely located on the Quarter Panels of your vehicle, or in some cases on the Rear Bumper or in the Tail Lights. The Grand Cherokee had Rear damage from a collision and the body shop worked on the Rear Bumper and Quarter Panels. After all the repairs were completed, the shop rightfully scanned the vehicle and no codes came back. However, when the vehicle was driven on the road the BSM visual alerts would illuminate almost the entire time while driving.
The shop was unsure what could be causing the problem and brought the Jeep to our shop. Once we talked with the body shop and found out exactly what they did to the vehicle, it was time for us to troubleshoot. We ended up taking the Rear Bumper off the car to take a look at the BSM units/modules themselves and noticed they didn’t look right. They were intact and the part themselves looked fine but the way they were situated on the vehicle did not seem correct. Then we noticed it, the BSM units/modules were right side in, meaning that the radar on the unit was pointed into the vehicle itself not out towards the vehicle's blind spot areas. This caused the BSM units to constantly read and pick-up a vehicle, itself ironically, hence why the visual alerts for the system would stay on almost all the time while driving the vehicle. These modules simply don’t know if they're facing the wrong direction and they assume that if they’re picking up a signal it must be in the correct line of vision. A quick fix by flipping the units around and a short road test on the highway confirmed that the BSM system worked correctly following the troubleshooting.
2. "If I scan a vehicle and the DTC isn’t in an ADAS module I don’t need to calibrate anything."
A lot of automotive shops out there think this. Unfortunately, it is simply not true. Like I stated before, everything in a vehicle can be connected in some way or another through the network. Many of the systems in a vehicle for example get information from the Body Control Module (BCM) to operate correctly. The BCM could have a DTC but the Front Radar Module (commonly known as RADAR, ICC, and/or ACC) could have nothing wrong with it but because the BCM has an issue it could cause the Front Radar to completely not work or not work correctly.
We learned this through multiple vehicles from different manufacturers and models but one calibration and vehicle really stuck out. Earlier in 2022 we worked on a 2018 Subaru Crosstrek Premium that had some front end work done to it as well as the windshield replaced, so because of this the Subaru Eyesight system, near the rearview mirror, needed calibration. Subaru’s Eyesight system provides features such as Adaptive Cruise Control (ACC), Lane Keep Assist (LKA), and Pre-Collision Braking (PCB). The calibration procedure involves a static calibration in our shop and a dynamic calibration on the road. Every car that arrives at our shop is scanned and then we clear as many codes as possible because certain DTCs will not allow calibrations to be completed. This Subaru was no different, and after scanning and clearing codes, the vehicle still had 2 DTCs related to the Engine, P0011 and P000A related to the Camshaft. From our perspective, it seemed like issues unrelated to the repairs so we continued as normal with the calibration. The static calibration went smooth in our shop but the dynamic calibration would complete and then the Subaru would light up like a Christmas tree after the initial key cycle following the completed procedure. Time for us to troubleshoot.
When we got back to our shop with the vehicle we were unsure what could be wrong but immediately looked back at the last scan and researched the 2 DTCs related to the Engine. To resolve those DTCs we found that the Upper Right Engine Variable Valve Timing (VVT) Solenoid needed to be replaced as it was cracked from the loss. We gave the vehicle back to the shop and when they replaced the VVT they returned the car back to us. Both the static and dynamic Subaru Eyesight procedures were attempted again and this time both were completed successfully. The key cycle after the dynamic calibration didn’t trigger or set-off any lights or dashboard messages and a road test following both procedures confirmed the Eyesight system worked properly.
The above examples are only a few vehicles that we’ve encountered that show why the two statements mentioned above are not always true. It’s important to get ADAS calibrations done when they are required, which means staying on top of what the manufacturer’s say and doing the research to determine when a calibration is needed for any vehicle you work on. Many people call us to ask whether or not a vehicle may need calibration and it’s a simple yet effective way to make sure the vehicle is returned to the customer in the correct condition, fully repaired right. Don’t think you are smarter than this new ADAS technology. Playing around or avoiding the calibration step will make you liable for anything that could go wrong with those ADAS systems throughout the vehicle.