TC Malfunction Visit Workshop message
Thread Starter
Junior Member
Joined: Nov 2021
Posts: 19
Likes: 1
From: Colorado
G550
TC Malfunction Visit Workshop message
I did a search on this forum and know this has been discussed before, but I don't see any definitive answers for "newer" G550's. I have a 2016 G550. Recently, I got this message on the display:
TC Malfunction Visit Workshop Apply Parking Brake to Park
The truck drives perfectly with no obvious mechanical problems. This is only the second time I have gotten this message. This message first appeared about a week or two ago but turned off when the car was restarted. Today, I started the vehicle and this message was displayed again. From some internet research and review of old posts, some have said this is not uncommon and could be related to a weak battery, while others have said it requires replacing the transfer case actuator. I'd appreciate any advice if any forum members have experience with this. I would like to fix it correctly and don't mind replacing the battery (batteries) if needed, but I know batteries are expensive in these trucks so I don't want to replace a battery just to troubleshoot this problem. Also, if it is a battery problem, which battery should be replaced, ie. the main battery or an auxiliary battery? Thanks for any help.
TC Malfunction Visit Workshop Apply Parking Brake to Park
The truck drives perfectly with no obvious mechanical problems. This is only the second time I have gotten this message. This message first appeared about a week or two ago but turned off when the car was restarted. Today, I started the vehicle and this message was displayed again. From some internet research and review of old posts, some have said this is not uncommon and could be related to a weak battery, while others have said it requires replacing the transfer case actuator. I'd appreciate any advice if any forum members have experience with this. I would like to fix it correctly and don't mind replacing the battery (batteries) if needed, but I know batteries are expensive in these trucks so I don't want to replace a battery just to troubleshoot this problem. Also, if it is a battery problem, which battery should be replaced, ie. the main battery or an auxiliary battery? Thanks for any help.
Thread Starter
Junior Member
Joined: Nov 2021
Posts: 19
Likes: 1
From: Colorado
G550
Thanks for that reply. I have read other reports of the aux battery causing this warning. I'm curious how the dealership troubleshoots this to determine it is the aux battery and not the transfer case actuator. I have an appointment to bring in the truck next week and believe they will likely replace both the actuator and aux battery (the aux battery may be original). The main battery was replaced 2 years ago so should be no problems there.
