Raise your Hy-Q

Jan. 1, 2020
If you’re like most repairers, you’ve already worked on hybrid vehicles and, odds are, they didn’t pose any particular difficulties.

If you’re like most repairers, you’ve already worked on hybrid vehicles and, odds are, they didn’t pose any particular difficulties. These vehicles have been around for more than a decade, and there’s plenty of repair information and safety material around to help you fix them correctly while protecting your employees and business.

Unfortunately, these same factors can in time work against you. Safety statistics show that businesses like shops run into some of their biggest problems handling potentially dangerous and sensitive products after they’ve spent several years working around them. The main reason: complacency sets in. This is a big reason why shops still have easily-avoidable accidents with welders, tools, caustic substances and flammable products. It’s the same reason why some shops still are hit with OSHA and other workplace safety violations. They get a little too comfortable with their work habits, stop sticking to all guidelines at all times and casually ignore new information.

Let’s put a stop to that with hybrid repairs. Here’s another look at the major repair and safety issues you need to attend to, along with some reminders of just how complex hybrid repairs can be.

Repairing hybrids goes well beyond identifying the orange, high voltage wires.

The basics
The two most basic rules regarding working on hybrids remain the same: the orange wires are the potentially deadly high-voltage lines. When working around them, you need protective gloves rated for 600 volts and over.

While avoiding the orange lines is easy enough to remember and follow, you need to keep one other point in mind. These lines remain dangerous at all times. Even if a manual disconnect device has been activated to allow the vehicle to be serviced, the energy potential within the battery cannot be disabled. You need to assume at all times that the battery, hybrid components and the orange wires still possess or carry 300 volts of electricity.

This remains true even if the battery has suffered severe damage. It must always be handled with caution and only by a trained technician since mishandling it can result in serious injury or death.

Moving, storing and starting
Moving most vehicles through your shop shouldn’t be a problem. Your biggest worry is typically is accidentally scratching against a wall, equipment or other vehicle. This isn’t the case with hybrids, particularly the latest models, which require special handling.

For example, never tow or push hybrids with all four wheels. Doing so can generate electricity,

Hybrid components are placed throughout a vehicle. You'll need to inspect and properly handle all of them to perform a proper repair.

which can cause the hybrid to move on its own and cause an accident. When towing, lift the front end or, better still, load the vehicle in a flatbed truck. When pushing a hybrid, use roller wheels to move it and make sure the key has been removed.

You also need to pay special attention to a hybrid’s other battery, its auxiliary gas engine battery. If you need to charge this battery, either use the manufacturer’s recommended charger when charging it or a regular battery charger that’s set it to the lowest rate, one no higher than 3.5 Amps. Using higher amperage can damage this battery.

Never leave the ignition key in "on position" when a hybrid vehicle is not being used since this can drain the auxiliary battery or, worse still, trigger its operation. This can be particularly important if you’re changing the oil and the vehicle starts after the oil has been drained.

If you refuel a hybrid, check the manufacturer’s recommendations on fuel octane. In many hybrids, using gas with a higher octane rating than 87 can make starting the engine difficult. You certainly don’t want your customers running into this problem after picking their vehicles up.

Watch where you cut
Sectioning hybrid vehicles or performing cutting of any kind can be potentially disastrous due to the placement of high voltage wiring and other hybrid and electric components throughout the vehicle.

Two rules apply here. One, never cut into a hybrid vehicle until you have first deactivated all the vehicle’s electrical systems. Two, always check the manufacturer’s repair instructions before cutting.

Always check the manufacturer’s repair instructions before performing any cutting on a damaged hybrid

Consider some of the cutting restrictions General Motors places on its hybrid models. They tell repairers not to cut:

  • The center of the vehicle since intermediate 36 volt wiring is routed in a conduit tube beneath the vehicle.
  • The roof rails between the windshield pillars and “sail” panels.
  • The area near the passenger side frame rail (300 volt wiring is routed near the frame rail on the passenger side of the vehicle).
  • Roof rails between the windshield and “D” pillars. The Chevrolet Tahoe and Silverado, GMC Yukon and Sierra, and Cadillac Escalade hybrids all are equipped with side impact air bags in these places.
  • Under the vehicle near passenger the side frame rail, which contains 300 volt electrical cables. Cutting also is restricted two feet farther back since this area houses the two-mode hybrid battery, which possesses a potential of 300 volts of electrical power at all times.

On the subject of deactivating all of a hybrid’s electrical system, this includes a vehicle’s 12V system. General Motors warns repairers not to cut into its hybrid vehicles until the 12V electrical system has been deactivated and isolated since doing so can cause the air bags to accidentally deploy, which can seriously injure a repairer.

Air bag accidents
Unintended air bag deployments, in fact, are a constant factor with any hybrid repair. Ironically, these deployments are related to safety features design to protect the vehicle’s occupants during a crash.

The contactors inside some hybrid batteries are engineered to open when one or more air bags deploy. This interrupts the electrical system and discontinues the current flow through the high voltage cables. This feature, among other things, protects occupants from electrocution following a collision.

This becomes a repair issue because techs end up working on vehicles with deployed airbags and disabled electrical systems. While this may sound safe, it really isn’t.

Even when a hybrid’s high voltage system has been disabled, the battery still possesses 300 volts of power. Work around it and handle with extreme caution.

The problem here is that these vehicles only cut the high voltage power during a collision, not the current passing through the 12V electrical system. If this current is running, it can still deploy dual-stage airbags that have not fully deployed. In other words, the airbags and electrical systems are still a repair and safety issue.

Repairers need to remain mindful of both electrical systems in a hybrid. Disabling the 12 volt power is essential to ensure personal safety even if the airbags in the vehicle appear to have been deployed.

To ensure you’re performing the disabling procedure properly, refer again to the manufacturer’s repair instructions. For example, GM states that after disabling 12V power on its vehicles, repairers must still wait at least 10 seconds to allow any un-deployed air bag reserve energy to fully dissipate.

Further safety system concerns
Repair challenges related to a hybrid vehicle’s safety systems don’t end with air bag deployments. That’s just one part of a larger repair issue that extends to the relationship between safety systems tied to the hybrid components and more traditional ones (present on every type of vehicle) designed to protect vehicle occupants from the impact of a collision.

Both of these safety systems utilize a system of sensors. On hybrid vehicles these sensors sometimes take on dual roles. Repairers must account for this factor in order to return all of a hybrid’s safety features to their full functionality.

Only a properly trained repairer should handle a hybrid’s lithium-ion battery. When replacing or disposing of one, be sure to contact a certified hazardous waste company.

For some perspective, let’s look again at GM products and repair instructions.

Like other GM models, their hybrid vehicles incorporate supplemental inflatable restraint (SIR) impact sensors that identify the severity of a collision and the direction from which a collision occurred, in order to help direct the deployment of passenger safety systems. Hybrids additionally incorporate high-voltage circuit impact detection (HVCID) sensors, usually located at the front of a vehicle, which detect collision damage to the high voltage system.

When there is either SIR deployment or the when the HVCID sensor detects a collision, the drive motor generator control module - also known as the hybrid powertrain control module (HPCM) - opens the high voltage contactor relays and disables the vehicle. Both sensors, then, can disable the high voltage system.

The HVCID sensor detection of a vehicle impact does not cause SIR deployment. Some collisions therefore can result in the vehicle being disabled without setting off the passenger safety systems.

The challenge repairers face is determining, in some cases, which sensors disabled the vehicle since those sensors will need to be cleared by a scan tool.

Inspection directions
Regardless of the source of the signal to disable a hybrid vehicle, repairers must thoroughly inspect the entire high voltage/electrical system before returning a vehicle to the owner.

A proper inspection must include the manufacturer’s recommendations since each hybrid make operates differently. Typical inspections begin with checking all high voltage wires for frayed lines, cracks and other damage. Repairers also must examine the rest of the hybrid components for similar damage.

From there, the inspection extends to an examination of other electric components for damage and wear. These components include:

  • The drive motor generator control module assembly.
  • The air conditioning compressor assembly.
  • The transmission assembly.

Repairers check each for dents, cracks and other physical damage and must replace any damaged components.

Only after all damaged high voltage and electric components have been replaced should a repairer use a scan tool clear the HVCID and/or SIR Deployed vehicle disable condition.

No bake zone and other issues
After a hybrid’s systems have been brought back up to snuff, repairers must be aware of one final repair issue, the paint work. Due to the sensitivity most hybrid batteries have to heat, a paint department must restrict the time and temperature a hybrid vehicle is subjected to in a paint booth. Some manufacturers do not recommend temperatures above 140 degrees Fahrenheit for more than 40 minutes since heating conditions more severe than this can damage these expensive batteries.

Should you need to dispose of or return a damaged hybrid battery, regardless of the reason, you’ll need to take special steps. Hybrid batteries, a type of Lithium-ion battery, are classified as Class 9 hazardous materials and therefore fall under special shipping regulations.

If you have any questions about compliance, refer to the shipping instructions packed with the replacement battery since they usually contain information on transporting returns. Take time to fill out the return transport paperwork properly and label the battery according to all federal, state, and local laws. Be certain the company you hire to do the transport is certified to handle hazardous material since you could be held liable for any broken laws, violations or problems created by a non-certified transporter.

Does all this seem complex? To some extent it is, but you deal with a host of similar issues when repairing vehicles that aren’t hybrids. The point here is that repairing hybrids involves taking into account a host of other safety and repair issues. Even a slight slip up can be costly or deadly.

Stay informed, aware and in business by giving these special vehicles the attention they demand.

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