Under the Hood: Use cellphone video to document tricky mechanical issues

McClatchy-Tribune Information Services

June 18, 2018

Q: We have a 2015 Hyundai Sonata Limited. It wasnít long after we purchased it, it developed the following problem: When I wanted to go into smart cruise control, it would refuse and indicate that SCC (smart cruise control) conditions are not met. The difficult part of this is that this would happen intermittently. The dealership checked it out numerous times over the past two to three years to no avail. Then they brought in a top engineer to check it out. They said he made full alignment of the system, and the problem still happens. They cannot replicate the problem. It seems this is the only Hyundai with this problem. The problem arises no matter what the weather, and, yes, the car is clean. It is in the garage most of the time. It has over 23,000 miles. Any ideas?

óRoy A.

A: Your smart cruise control system employs a radar sensor and smart integration between the powertrain, braking and other control modules to adapt to traffic ahead and maintain a safe following distance relative to the speed youíve requested.

The list of possible disabling conditions is lengthy, with a dirty, misaligned, or faulty radar unit included.

Hereís a question for you: When the SCC system is unavailable, are you able to engage the basic cruise control instead (press and hold the "distance" button for two seconds)? If so, this would rule out about 90 percent of the items on the list.

As with all intermittent problems, carefully detailing the conditions present at the time of symptom is essential. Having a passenger record a phone video of an unsuccessful smart cruise control engagement attempt, narrated with appropriate comments would solidify your concern (car companies prefer this word over complaint) and help you pressure Hyundaiís customer service folks to get that engineer back on it, and perhaps replace the integrated radar/SCC control unit. Seeking a repair attempt as soon as possible after a failure provides the best chance of holding any stored diagnostic trouble codes in memory.

I searched for applicable service bulletins and cast a wide net for similar concerns but came up empty. This appears to be a unique problem. Turn up the heat with that video!

Q: My red battery indicator has begun to light up at certain times. What could cause this?

óDave W.

A: Depending on the vehicle, there could be several possible causes for this; usually itís because the alternator is not supplying sufficient energy for vehicle use and battery state of charge. Alternator is a term used for a vehicleís belt-driven electrical generating device; it converts the engineís mechanical energy into electrical energy.

With the engine off and cool, try grabbing and rotating the alternatorís pulley against the stationary drive belt. If you can slip the pulley at all, belt tension is inadequate. Also check the battery terminals for looseness and/or corrosion. Alternators typically employ brushes, which are small carbon electrical conductors that ride against the rotorís slip rings. The rotor becomes a multiple-pole magnet, the heart of the generating process. Due to friction, brushes eventually wear out, lasting perhaps 125,000 to 150,000 miles. This may be whatís causing your intermittent charging system light. Brushes are inexpensive but due to the labor involved to renew them in most cases itís simpler to swap out the alternator with a remanufactured unit.