Some prius, prius v, and prius phv vehciles may eexhibvit a rough idle or tapping noise from the HV...

Bulletin number

T-SB-0027-16

Component

Engine and engine cooling: exhaust system: emission control

Summary

Tsb: some prius, prius v, and prius phv vehciles may eexhibvit a rough idle or tapping noise from the hv transaxle at cold start. The check engine light may also illuminate with (dtc) p0401 (exhaust gas recirculation flow insufficient detected). Due to excess carbon build-up at the valve assembly, the valve will stick, causing the engine RPM to fluctuate. Follow the procedures in this bulletin to address the condition.

Owners of these vehicles have filed 297 complaints in the engine category.