I've had my low mileage 05 Roadster now for a few years...and love it. Recently though I have 3 warning lights that are frustrating. The low coolant light remains on. I replaced the sensor and it remains on. Coolant level is fine. Likewise, the tire pressure light stays on. All 4 sensors have been checked and are fine, as are tire pressures. Finally, the BAS/ESP warning light is intermittent. I read the owner's manual on how to turn it off. That didn't work. It does as it pleases!

The local Chrysler dealership wants a $120 to diagnose these issues. Service manager admitted they don't have a Mercedes analyzer. Should I take it to a Mercedes dealer (90 miles)? Any advice would be appreciated.

 

Call first, usually Mercedes dealers will not touch a Crossfire. Check for Mercedes Independents in your area. How do you know if the batteries are not bad in your TPMS sensors?

 

There is no "low coolant light" - that light is "the general cooling system alarm light" and it comes on for any of the following reasons:

• Low Coolant
• Bad Coolant level sensor
• The ECM does not get the proper response to it's periodic "tickle pulses" from the Fan Control Module
• The Fan Control Module reports out-of-specification current flow in fan motor
• Indication of higher than normal water jacket temperature
• Probably other reasons I don't know about

Troubleshooting that light can get involved, but it need not be hard. A complete understanding of the interaction between the ECM and FCM is what is needed. I would think that any MB shop with competent people working in it would be able to find this for you, this system is not unique to the Crossfire/SLK320, they used the same concept in millions of MB cars.



Checked by who and with what instrument?

• ANY sensor reporting a high or low pressure will light the light.
• ANY sensor failing to report will light the light.
• Given the age of the car, I'm sure you have at least one sensor with a battery that has expired.

This can be a bad wheel speed sensor, bad yaw sensor (that IS what it's called, right?), flaky battery or corroded/crappy battery cables/terminals. There may be other causes, but those are what I know of.
Again, this system is used in millions of MB products.

Go find an independent shop known for MB expertise and see if they can help you.

 

Took car to Discount Tire and they checked all sensors. They said all are OK.

 

Sounds pretty complex to me. Will take advice and seek out MB experts.