2015 FR-S Shaking in Idle & Code Problems

[ammtx]

Hi All,

I have a 2015 Scion FR-S with 147,800 miles. I bought it at auction about 6 months ago and haven't been able to identify the problem. The car shakes noticeably while in idle. Once I drive it, the shaking goes away. But when I stop at a light, or while parked, it shakes... a lot!

The scanner is pulling up codes P2158 (speed sensor), and code P2401 (EVAP Leak). We completed a smoke test, but there's no visible leaks. We replaced the speed sensor, but the code persists. We switched the right speed sensor (reported problem) with the left speed sensor, and the problem persists. We switched out the ECU and had a programmer come to reprogram it, but the shaking and codes persist. After deleting the codes, the EVAP code erases and the shaking reduces. But, just seconds later, the shaking starts up again and the code re-appears. The ECU programmer said he thinks it's bad grounding on one of the many wires.

Has anyone else encountered this issue? I've seen posts with these codes before, but never at the same time.

What are your thoughts?

**Also, the engine fan is constantly running despite not reaching the required temperature to run.

[soundman98]

if your a/c is on/enabled, that'll force the fan on.

at 150k miles, i'd be suspicious of first the spark plugs, and second, the coil packs.


my rule #1 of buying a used vehicle-- unless you've got a receipt for maintenance performed, assume zero maintenance was ever performed.

at 150k, i'd be changing all the fluids, checking belts and tensioners, changing the cabin air filter, change engine air filter, check battery life, and do spark plugs and coils.