Here's How To Fix The Scion FR-S And Subaru BRZ Engine's Idle Problem

The Scion FR-S and Subaru BRZ twins have been some of the most acclaimed driver's cars we've seen since the original Mazda Miata hit the road. We know people love carrying kids in them, drifting them, and then, unfortunately, crashing them after drifting them.

But an engine issue has arisen in a number of cars that could actually cripple all of that driving excitement the cars bring with them. Here's how to get it fixed.

The Scion and Subaru both use a boxer four cylinder engine that suits the lightweight character of the car perfectly. It might not be the most powerful engine on the market, but it makes up for that with character and chutzpah.

It's the little engine that could… or is it?

Members of the FR-S, BRZ, GT 86, and 86 fanclub, FT86club.com, have detected a fault in a number of cars that occurs at idle:

This idle issue may manifest itself as an initial dip... if you have experienced a combination of the check engine light (CEL) and slip light (SL) in addition to the RPM hunting at idle (often severe shaking and stalling). The code your ECU should have stored is P0019 (also optional P0017, P0018 or related cam codes).

At low RPMs, an issue is causing the cars to shudder, idle rough, and in some cases stall. And it isn't five or ten cars. FT86 Club has 121 owners listed that have experienced the issue, which means it is probably apparent on more cars that aren't owned by forum members.

Some of the cars had just eight miles on the odometer when the issue surfaced, and then spent a few weeks in the dealer to get fixed. As you would expect, the owners weren't that happy of a bunch.

But Toyota is coming to the rescue for FR-S owners. We spoke to them today, and were told the below:

In a matter of weeks of detecting a diagnostics sensitivity accompanied with rough idle phenomenon, we deployed an ECU update into production and to our customers. The condition is brought on by a combination of normal mechanical variables (similar to tolerance stack up) aggressively monitored by the ECU. Dealers now have the reflash to correct the issue.

So the problem has been tracked down and you can get your ECU reflashed at your local Scion dealer for free. There is currently no active recall for the cars, but the dealers should know what's up if you tell them about the issue.

But what about the Subie owners in da house? We'd imagine those dealers have the ECU fix as well, but Subaru has not yet responded to our inquiry about the issue.

UPDATE: Subaru just responded to our question about the issue, and they will also reflash cars with an issue:

Just to clarify, this is a simple ECU mapping issue that is fixed using a re-flash of the ECU and it is an extremely rare condition found in a small number of US Subaru BRZ vehicles. Customers will be alerted to the issue by a check engine light.

The condition causes no damage to the engine and a TSB is in-process.

It is not related to mileage and no replacement of the ECU is needed at any mileage to rectify the issue, the ECU re-flash is the fix.

The issue is caused through the ECUs reaction to normal mechanical variations and is statistically very small. There has already been a fix at the factory level and it was an ECU mapping change, not an engineering process or mechanical modification. The ECU mapping was too restrictive in the original mapping set up.

(Thanks for the tips everyone!)