Becoming radar-ready Part 2

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What you will learn:

• ADAS systems will create a new set of symptoms, still unknown to many

• ADAS is an acronym to represent multiple driver's assist systems

• Some ADAS features can be disabled by the driver

You're making a quick post-repair quality check (via a road test) as a final step in completing a collision repair job when you notice the vehicle seems to have a “sluggish” feel in the steering wheel. Do you need to reopen the estimate and head to the local alignment shop for some anticipated front-end work? Did any of the ADAS (advanced driver assistance system) sensors become damaged or misaligned from the collision? That "sluggish feel" in the steering wheel may be normal.

Does the vehicle have a lane keep assist (LKA) option? Were you changing lanes when you felt the sluggish steering sensation? Did you forget to use your turn signals?

You've solved the problem if you admit “Yes” to not using turn signals while making a lane change. LKA can’t “read our minds” any more than the other drivers on the road when we don’t signal.   

LKA systems can apply a little “persuasion” to the EPS (electric power steering) to prevent the vehicle from drifting out of its present lane. In this second article on becoming “radar ready”, we’ll go beyond Part 1’s discussion of the technologies used in ADAS systems to focus on human factors and simple diagnostics. The first step in diagnosing any problem is determining exactly what’s normal regarding operation. As the old saying goes, “If it’s not broke... you can’t fix it!”  

Mission 1 - Determining what’s 'normal' (is it broken?) 

A collision repair shop rarely has the luxury of driving a vehicle (without a problem) before a repair. Vehicles involved in collisions are broken before we drive them! Describing what “normal” feels like is difficult to put into the confines of the text in a repair manual. Remember that "broken" may translate into "simply out of calibration." Improperly calibrated/uncalibrated sensors may or may not set a DTC. That means the pre- and post-repair scans are not 100-percent at catching problems. 

I was on a long interstate highway trip this year in a rented 2021 Toyota RAV4 with all the latest ADAS features. The RAV’s LKA was working hard to maintain the lane where “it thought” the vehicle should be driving. I was constantly fighting the wheel to keep a straight line within the lane where I thought the vehicle should be driving.  My choices were to turn off LKA or heed advice from the lyrics of a song that just happened to be playing on my Rav’s radio that day:

 “Just hold on loosely but don't let go. If you cling too tightly, you're gonna lose control (From “Hold on Loosely” by 38 Special)."

  So, I tried keeping both hands on the wheel (loosely) to allow the RAV’s LKA to have slightly more straight-line lane control than I, and it worked! No more “sluggish steering"!

3 steps for getting yourself 'radar-ready'

1. Become familiar with as many different ADAS-equipped vehicles as possible (various OEMs, trim levels, and model years) to gain insight into the variations in ADAS-equipped vehicles.
2. Always verify that the vehicle has the optional equipment you 'believe' is not working correctly. You can’t fix what’s not broke – or doesn’t exist. (Figure 1).
3. Determine which variation of ADAS system is on the vehicle you’re repairing. To assist with learning the details of what is normal, the vehicle owner’s manual can be helpful, along with a VIN decoder website. Another good resource is NHTSA's site, which is free and to the point in defining these systems.

Improvised ADAS sensor diagnostics 

• Fuzzbuster (checks lower band radar sensors for operation) 

A police radar detector placed near early (24 GHz) blind spot radar sensors (key on) can help determine if the sensors are plugged in and functional. The radar detector will falsely trigger if moved close to the sensor. Later models operate on frequencies in the upper 70s GHz region, which tend to eliminate radar detectors and blind spot monitor false triggers.  

• Thermal image camera / digital pyrometer (checks for available voltage / ground supply) 

Radar sensors and LKA/collision avoidance cameras create heat. If they’re plugged in and powered up, they’ll have a heat signature. Some vehicles will even list a PID (parameter ID) in the scan tool data stream, to help you determine if its forward view camera sensor's heater is turned on (to prevent windshield fog in front of the sensor) or stuck on (creating a problem).

For health reasons, more powerful ACC radar sensors don’t turn on until the vehicle is ready to move and the ACC ready to activate (or in static calibration mode) (Figure 2).

• Mechanic’s stethoscope (checks ultrasonic parking sensors) 

The frequency of the actual signals these round bumper-cover mounted sensors make is inaudible to the human ear, but the vibration associated with their operation can be easily heard with a mechanic’s stethoscope (rapid clicking) placed on the sensor (when activated).

• Sensor replacements, chassis alignments, and windshield replacements are just a few tasks that can trigger the need to calibrate ADAS sensors. Thrust alignment must be performed correctly (no dog tracking) before any calibration or the sensor will "see" the exact wrong thing. 

• While some medium-range blind spot radar sensors are "plug-and-play", others require a target (radar signal reflector) placed in a precise spot near the vehicle in a manner described by the OEM. 

 Static (in shop) calibration targets 

1. Visual pattern targets (for cameras) 
2. Metal reflector target (for radar sensors)  

 Static (in-shop) calibration equipment types 

OEM vs. aftermarket tools and techniques 

Having the right tools on hand has always been important with any automotive repair, but it still comes down to the human factor (Figure 3). The ability of a technician to accurately follow all of an OEM’s calibration instructions will be the deciding factor in becoming "radar-ready."