Maybe Subaru's Soy-Based Wiring Is Too Eco-Friendly?

TL;DR

Rodents just can't resist the soy-derived wire coatings used in many Subaru vehicles. The chewed up wires are costing owners hundreds, and sometimes thousands of dollars in repairs but Subaru, like other automakers, insists this isn't a defect.

A very fat mouse.

Subaru prides itself on its eco-friendliness. They claim to be America’s first zero-landfill automaker[^1], and have made the switch to a more environmentally friendly, bio-degradable wire coating that is derived from soy.

But just like showing up with a tofurkey at the holidays, not all earth-friendly changes are without consequences.

The Pros and Cons of of Soy Wire Coating

The most obvious benefit of coating wires in soy-based materials is it results in less plastic in the landfill or oceans. That’s a good thing!

And the soy-based materials tend to be cheaper than their plastic counterparts, saving the automaker money. Now theoretically they could pass those savings on to the consumers, but let’s just say one way or another that saving money is also a good thing.

However there are also downsides, depending on your perspective.

The coatings are a perfect chew toy for rodents, provide excellent nesting material, are are found in near endless supply in a warm, hidden spot. If you’re a mouse, it’s the greatest thing ever. But if you’re an owner waking up to a severed fuel line, it’s a little less enjoyable.

Subaru is not the only one to make this switch or deal with the rodent-problem

In January 2016, a lawsuit filed against Honda claimed the soy-based wiring was irresistible to rabbits. Later that year, a similar lawsuit was filed against Toyota. In July 2017, both Hyundai and Kia were sued for using soy wiring.

In each case, the automaker was accused of concealing the problem and/or refusing to fix the issue under warranty.

Replacing a fuel line or running new electrical wiring is not cheap

Typically owners report paying a couple hundred dollars for repairs, but that’s if they’re lucky. In some cases rodents have been known to chew through wiring harnesses or wires in the automatic transmissions, costing $2,433 and $1,200 to fix respectively.

Prevention options get really, really weird

Search the Internet for how to keep rodents away from your car and you’ll see everything from peppermint spray, to tape laced with capsaicin, to the less than desirable “coyote pee” option as explained in this Forbes article:

Every night, Joann's pours a little coyote piss around her tires. "I dot my driveway with some too," she says. She also places a  Coyote urine-soaked sponge inside a tin pan near the car. She's not sure it's working yet and does not want to take her car in for any more repairs until she's rid of the rats once and for all.

If I had to do that every night it’d really piss me off.

Subaru Class-Action Lawsuit in Hawaii

In November 2017, Subaru joined the list of automakers sued for using soy-based wire coating. The lawsuit is filed in Hawaii and limited to a certain dealership, but the verdict may result in state-wide or nationwide action.

Plaintiff Joy Diane Shuey says she purchased a new 2015 Subaru Forester from Servco Subaru, but about a month later she took the SUV back to the dealer because of a fuel odor and an illuminated check engine light … The Servco technician allegedly discovered the fuel line and rear wiper hose needed to be replaced because they had been chewed by rats. Shuey says she paid $318.52 for repairs that Subaru didn't cover under warranty.

So once again we’re seeing the same story line: automaker uses soy-derived products → rodents see their opportunity and cause damage → damage isn’t covered under the automaker’s warranty.

What really gnawed at the plaintiff was how later that month, she was charged $2,433.30 to replace an engine wiring harness that had been chewed through.

In general, Subaru’s response is the same as Honda, Toyota, and other manufacturers: this isn’t a defect, invest in some coyote pee, or maybe get a garage cat.

[^1]: From Subaru’s Own Environment page.

Models With Rodents Chew Subaru's Soy Wires Problems

Subaru Legacy

PainRank
6.74
Complaints
264
Reliability
10th out of 17

Subaru WRX

PainRank
12.48
Complaints
75
Reliability
14th out of 17

OK, Now What?

Maybe you've experienced this problem. Maybe you're concerned you will soon. Whatever the reason, here's a handful of things you can do to make sure it gets the attention it deserves.

  1. File Your Complaint

    CarComplaints.com is a free site dedicated to uncovering problem trends and informing owners about potential issues with their cars. Major class action law firms use this data when researching cases.

    Add a Complaint
  2. Notify CAS

    The Center for Auto Safety (CAS) is a pro-consumer organization that researches auto safety issues & often compels the US government to do the right thing through lobbying & lawsuits.

    Notify The CAS
  3. Report a Safety Concern

    The National Highway Traffic Safety Administration (NHTSA) is the US agency with the authority to conduct vehicle defect investigations & force recalls. Their focus is on safety-related issues.

    Report to NHTSA