# Service bulletin SSM 49099

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: 10181869
- Published by NHTSA: 2020\-11\-04
- Manufacturer's number: SSM 49099
- Manufacturer's date: 2020\-10\-16
- NHTSA component: POWER TRAIN; POWER TRAIN:TRANSFER CASE \(4\-WHEEL DRIVE\)

## NHTSA's summary

2019\-2020 F\-150 vehicles equipped with four\-wheel drive \(4WD\) have a revised transfer case control module \(TCCM\) strategy that will affect integrated wheel end \(IWE\) operation after initial start\-up. The TCCM will not energize the solenoid to supply vacuum to the IWEs after the initial key cycle and a driven gear is selected. The IWEs will remain engaged for 0.8 km \(0.5 mi\) when the temperature is above 0 deg C \(32 deg F\) and 3 km \(2 mi\) when below 0 deg C \(32 deg F\). The strategy changes were implemented to improve vacuum supply management and axle warm up in cold temperatures. The engine must run for a minimum of 5 minutes to build sufficient vacuum before performing any vacuum related testing. Refer to the Workshop Manual \(WSM\) Section, 307\-08A \> Four\-Wheel Drive Systems \> System Operation and Component Description for additional information.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181869-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2020/MC-10181869-9999.pdf)

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

## Components

Transmission and driveline, Transfer case

## Vehicles listed

- 2019 to 2020 FORD F\-150

JSON: [/v1/bulletins/10181869](/v1/bulletins/10181869)

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