Check Fire Extinguishing System Temperature Sensor - AR86.10-P-0124SG

Model 223 

with code Z07 (B7 armoring on special protection version) 

with code Z21 (Fire extinguishing system) 

Courtesy of MERCEDES-BENZ USA

	Remove/install
1	Switch off ignition and remove transmitter key.
2	Remove rear panel trim.		AR68.30-P-4750SG
3	Remove electrical fuse 5, special-purpose vehicles (F80/1f5), and electrical fuse 7, special-purpose vehicles (F80/1f7) from special-purpose vehicle fuse block (F80/1).	Special-purpose vehicle fuse block (F80/1) is located at top right in trunk, behind rear panel trim. This prevents the fire-extinguishing system from being triggered by mistake. The wiring diagram documentation for this model series can be found in DWD (Dynamic Wiring Diagram). https://ws-retailfactory-dyna.mercedes-benz.com/start-aspu/
4	Lift vehicle with lifting platform.		AR00.60-P-1006A
5	Clean temperature sensors (B65/3, B65/4, B65/5, B65/6, B65/7, B65/8).	Do not use hard objects for cleaning, use compressed air. Temperature sensors (B65/3, B65/4, B65/5, B65/6, B65/7, B65/8) will otherwise be damaged. Contaminated temperature sensors (B65/3, B65/4, B65/5, B65/6, B65/7, B65/8) can impair the function of the fire-extinguishing system.
6	Check temperature sensors (B65/3, B65/4, B65/5, B65/6, B65/7, B65/8) and their electrical feed lines for damage and that correctly seated in brackets.	If a temperature sensor (B65/3, B65/4, B65/5, B65/6, B65/7, B65/8) is damaged, ↓ replace corresponding temperature sensor (B65/3, B65/4, B65/5, B65/6, B65/7, B65/8).
		Remove/install engine compartment fire-extinguishing system temperature sensor (B65/3, B65/4)	AR86.10-P-0127SG
		Remove/install front fire-extinguishing system temperature sensor (B65/5, B65/6)	AR86.10-P-0126SG
		Remove/install rear fire-extinguishing system temperature sensor (B65/7, B65/8)	AR86.10-P-0125SG
7	Install in the reverse order.