# Service bulletin 09\-110\-23

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 10244906
- Published by NHTSA: 2023\-11\-06
- Manufacturer's number: 09\-110\-23
- Manufacturer's date: 2023\-10\-09
- NHTSA component: ENGINE AND ENGINE COOLING; EQUIPMENT; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:CATALYTIC CONVERTOR

## NHTSA's summary

This Service Information Bulletin announces diagnostic service procedures to be followed when DTC P0420 \(Catalyst System Efficiency Below Threshold Bank 1\) is detected by the Engine Control Module \(ECM\). If DTC P0420 is found to be stored in the ECM, follow the diagnostic procedures outlined below.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2023/MC-10244906-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2023/MC-10244906-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Engine, Equipment and accessories, Exhaust and emissions, Catalytic converter

## Trouble codes named

P0420

## Vehicles listed

- 2019 to 2021 SUBARU ASCENT
- 2017 to 2023 SUBARU CROSSTREK
- 2017 to 2023 SUBARU FORESTER
- 2017 to 2023 SUBARU IMPREZA
- 2017 to 2023 SUBARU LEGACY
- 2017 to 2023 SUBARU OUTBACK

JSON: [/v1/bulletins/10244906](/v1/bulletins/10244906)

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