2017 Mercedes Benz C 43 AMG Diagnostic and Repair# S-80_61-59 Date: 121022

Keyless System/Instruments - 'Replace Key Battery' Displayed
Date: October 22, 2012
Order No.: S-B-80.61/59
Group: 80
SUBJECT:
All Model Vehicles with Keys Having One Battery
Instrument Cluster Message "Replace Key Battery" Appearing Soon After New Key Battery Replacement
Customer Complaint: The message "Replace Key Battery" is displayed in the instrument cluster not long after the key battery was last replaced
Condition/Background: If the battery was recently replaced and the customer has this message in the Instrument Cluster, Product Technical
Support is interested in gathering more data to determine the root cause of this issue.
Action: Please open and close a PTSS case and include as much of the following information that is possible to obtain:
VIN - Vehicle's VIN
Key Date Code - Date code of the key that is experiencing the issue (last 4 digits on barrel)
1st Batt Repl - The last time the customer came in to get a new battery in their key
2nd Batt Rep - The date that the customer came in with the low battery message in the instrument cluster, requiring another battery replacement
Brand - The brand of the battery (Duracel, Panasonic, etc.)
Source - Where the battery came from (e.g. the PDC, local Walmart, etc.)
Tensioned - The last time the customer came in, were the key battery contacts tensioned?
Enhanced - The last time the customer came in, were the key battery contacts cleaned/enhanced?
Driving Frequency - How many times a day, on average, does the customer get in and out of their vehicle? Do they get in and out 20 times, 2 times,
8 times?
Ride length - What is the average drive length per drive cycle? This is important because the KG system pings the keys every 5km for 20km - for a
total of 5 times per drive cycle max.
Driving habits - Where does the customer keep their key when driving?
Parking Habits - Where does the customer park their car? Do they lock it? Do they keep the key in the vehicle overnight?
When creating the case, please use the symptom string >Overall vehicle>Safety and locking system>Locks/locking/Remote closing
mechanism>Discharged battery. Finally, replace the key battery with a new battery by lightly and carefully tension the contacts, cleaning the contacts
using contact cleaner, and using a clean cloth to insert the battery into the key.