# Service bulletin N192266750

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: 10167472
- Published by NHTSA: 2019\-11\-12
- Manufacturer's number: N192266750
- Manufacturer's date: 2019\-10\-01
- NHTSA component: ENGINE AND ENGINE COOLING

## NHTSA's summary

N192266750 \- Service Update. On certain vehicles that are equipped with a 6.6L diesel engine, may have one or more of the following conditions exist: 1.The instrument panel cluster may incorrectly display the message ?DEF Low? when a diesel engine fluid \(DEF\) controller internal fault is detected \(DTC P20FF\), instead of displaying the proper ?Service DEF System? message. 2.The customer may complain of excessive engine fan noise at a low vehicle speed. 3.Under certain conditions, the diagnostic system may set one of the following DTC?s when there is no problem with a component: \(P20EE, P226D, P16F3 and P129F\). Dealers are to reprogram the engine control module.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2019/MC-10167472-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2019/MC-10167472-9999.pdf)

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

## Components

Engine

## Trouble codes named

P129F, P16F3, P20EE, P20FF, P226D

## Vehicles listed

- 2020 CHEVROLET SILVERADO 4500
- 2020 GMC SIERRA 2500

## Other bulletins for the same vehicles and component

- [00\-06\-01\-026R](/bulletins/11026017.md), 2025-12-03, Service bulletin: ENGINE. This service bulletin provides information on replacing the intake manifold when the engine is replaced after severe internal engine damage.
- [23\-NA\-170](/bulletins/11024486.md), 2025-10-25, Service bulletin: ELECTRICAL SYSTEM; ENGINE. This bulletin advises the tech to inspect deeper into what may be to main cause of an engine failure.
- [23\-NA\-153](/bulletins/11024485.md), 2025-10-25, Service bulletin: ENGINE. The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is opened rapidly and advises the customer that it is normal for the delay.
- [24\-NA\-241](/bulletins/11024332.md), 2025-10-16, Service bulletin: ENGINE. This informational bulletin advises the technician of a part number change for long block engines used in the trucks noted.
- [22\-NA\-080](/bulletins/11024330.md), 2025-10-16, Service bulletin: ENGINE. This technical bulletin provides a procedure to replace the camshaft actuator magnet to correct customer concerns of engine related shudder.
- [15\-NA\-010](/bulletins/11020254.md), 2025-07-07, Service bulletin: ENGINE. This service bulletin provides information to dealership personnel for new vehicles with less than 1,000 miles that may not pass California smog inspection or smog inspection in other states.
- [25\-NA\-037](/bulletins/11019748.md), 2025-06-26, Service bulletin: ENGINE. This bulletin advises the tech that the Exhaust Roller Follower may be the issue with the engine Ticking noise, misfire or rough run and what to replace if found the cause.
- [25\-NA\-100](/bulletins/11019503.md), 2025-06-12, Service bulletin: ENGINE. This warranty administration bulletin provides policy information on vehicles outside of a California Emissions State who move to and register their vehicle in a California Emission State may be entitled to the 7 year, 70,000\-mile Emission Select State Component Limited Warranty.
- [21\-NA\-139](/bulletins/11017443.md), 2025-05-01, Service bulletin: ELECTRICAL SYSTEM; ENGINE. This service bulletin provides a repair procedure to correct a customer concern of a Malfunction Indicator Lamp \(MIL\) Illuminated \- DTC P3055 Set.
- [25\-NA\-076](/bulletins/11017302.md), 2025-04-29, Service bulletin: ENGINE. This informational bulletin advises the technician that the gasket for the timing chain tensioner is not required.

JSON: [/v1/bulletins/10167472](/v1/bulletins/10167472)

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