Rough idle or stalling on early cars (ECU software)
Added · Updated
What causes "Rough idle or stalling on early cars (ECU software)" on the Toyota 86 / Subaru BRZ / Scion FR-S (ZN6/ZC6, 2013-2020), and how is it fixed?
A software error in the engine computer's valve-timing monitoring on early cars. Fix: An ECU reflash.
Symptoms
Rough idle or stalling, usually with a check engine light and code P0019, on early 2012-built cars.
Cause
A software error in the engine computer's valve-timing monitoring on early cars. Both automakers said it was software, not a mechanical defect, but some owners reported repeat faults and parts replaced.
Fix (summary)
An ECU reflash. In 2012 Toyota said cars past about 100 miles would get a replacement ECU, while Subaru said a reflash alone fixes it. Cars delivered after mid-August 2012 were said to have the corrected software. Not a recall.
Other ZN6/ZC6 problems
- Valve spring recall (2013 BRZ and FR-S)
- Low-pressure fuel pump recall (2018-19)
- Key can come out when not in Park (FR-S and 86 automatics)
- Oil seepage from the cam plate, cam carriers or timing cover
- High-pitched chirp or cricket noise from the engine
- Creaking clutch pedal
More for this car
- All Toyota 86 / Subaru BRZ / Scion FR-S (ZN6/ZC6, 2013-2020) fitment answers · ZN6/ZC6 common problems
- Newsletter archive: past issues with every new and corrected entry
Sources
- Rough idle problem hits Scion FR-S, Subaru BRZ coupes — Autoweek (Automotive News report, Oct 2012) (editorial; read 2026-10-26; full page read)
Summaries are in our own words. Not repair instructions; consult the factory service manual.
Report a correction — spotted an error or have a better source? Email hello@chassisdex.com.