Hi, Love your video on repairs.
My 1998 Mercedes SLK Kompressor have about 113000 miles. It’s an automatic transmissions. Been a nice car until couple years ago when I can’t get it to pass smog test due to check engine light. Then the speedometer start acting up. It would work perfectly one day then decided to quit another day. It seems to have a mind of its own. Please advise.
Ed
This is one of many common problems on Mercedes vehicles. The problem is likely to be Speed Sensor or Control Unit / Transmission Control Unit (TCU) or Speedometer / Cluster Gauge assembly issue (including cold-solder joints) and/or electrical / connector issue. ---- If you want to start investigating, start with the Check-Engine codes. Note: If there are multiple codes that are Speedometer / Speed Sensor / TCU related, then it's possible that a common "single point of failure" affects each. When troubleshooting, locate a service manual (I usually use Factory / OEM Service Manuals only / FSM) and perform any test / troubleshooting procedures before replacing / swapping parts. ------- this said, This will likely cost some $$$ and Mercedes past late 80's / early 90's are known for swallowing entire back accounts so be aware of this. ----- Bottom line, if you want to try to save it / learn how to repair then use a FSM and test before sinking additional $$$ into it. You can find digital FSM online. As an example (but do your own research as well), on EBAY we find: https://www.ebay.com/itm/Mercedes-Benz-R170-SLK-230-Kompressor-320-35-AMG-Service-Manual-Collection-CD/114313810479?hash=item1a9da2522f:g:IGoAAOSw~1NfFZrB
Hi @ ronjr, welcome to the forum. It’ll be a good idea to copy paste your ‘comment’ as an ‘answer’ below, where it’ll be more visible. Thank you.
This is one of many common problems on Mercedes vehicles. The problem is likely to be Speed Sensor or Control Unit / Transmission Control Unit (TCU) or Speedometer / Cluster Gauge assembly issue (including cold-solder joints) and/or electrical / connector issue. ---- If you want to start investigating, start with the Check-Engine codes. Note: If there are multiple codes that are Speedometer / Speed Sensor / TCU related, then it's possible that a common "single point of failure" affects each. When troubleshooting, locate a service manual (I usually use Factory / OEM Service Manuals only / FSM) and perform any test / troubleshooting procedures before replacing / swapping parts. ------- this said, This will likely cost some $$$ and Mercedes past late 80's / early 90's are known for swallowing entire back accounts so be aware of this. ----- Bottom line, if you want to try to save it / learn how to repair then use a FSM and test before sinking additional $$$ into it. You can find digital FSM online. As an example (but do your own research as well), on EBAY we find: https://www.ebay.com/itm/Mercedes-Benz-R170-SLK-230-Kompressor-320-35-AMG-Service-Manual-Collection-CD/114313810479?hash=item1a9da2522f:g:IGoAAOSw~1NfFZrB
I’m gonna assume you don’t wanna spend the money to fix it, in that case, sell it as is.
Usually, there’s no cheap/easy fix for a Mercedes as they almost always turn into endless money pits as they start to age.
If however, you do wanna fix it, prepare your wallet and start with scanning for codes.
