I have had a interesting problem with my 1998 s320.

a couple weeks ago I was driving and noticed the instrument panel had "frozen". The speedometer was stuck at about 45, the tach was stuck at about 2400 and the parking brake light was on, but the parking brake was released. Everything else on the cluster was dead including turn signal indicators, etc. (although the turn signals did work on the outside). Everything else in the car worked as normal.

The car ran fine so went home. I started checking fuses, but did not find any of them blown. I did remove two of the instrument fuses and re-install them. After doing that, the inturment panel was working right, but I had a CEL. I checked the codes (I have a Innova 3100a code reader) and it was a P1747 code. There was some "freeze frame" data:

can sig from etc
fuel sys 1 CL
fuel sys 2 fault
etc 197
stft 2.34
c, ev, 2a, 0, 0h
on

I reset the OBD and the CEL has stayed off, but when I check the OBD system I get about half of the indicators flashing meaning that these systems have not run their diagnostics.

One thing I have not done (keep forgetting) is to disconnect the battery for a while and see what that may do.

The car is running fine, and everything seems to be working ok.

Has anyone had a problem like this, or does anyone have some good ideas?

Thanks for any information.
Harvey

On that model the cluster is just a computer, networked.

Most likely a voltage issued caused that problem.

Readiness issues are usually based on the operation of the front O2 sensors.
Low speed driving is the key to passing the readiness flags.

__________________
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Thanks for your fast reply.

My original question had to do with some of the Monitor Status indicators were showing that they had not run. Part of them had and part of them had not.

I had not checked the OBD system for a while, so connected my tester this morning and found the indicators that were flashing as "not run", have now changed to "Have run diagnostic testing". There are no DTCs present.

Maybe it just needed some time to be driven and reset some things ? ? ?

I did notice that only 8 of the 11 monitors were showing active, but as I understand some cars do not have all 11. Would that be correct?

Thank you very much for all your information. I really appreciate it!

Harvey

Readiness is all about the way thay the car is driven.

here is an example

Attached Files

readiness.pdf (46.9 KB, 155 views)

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks for the info. The PDF file is interesting.

I do have one more question if you don't mind.

Prior to all of this happening, It was showing a "small leak" in the evap system. It was not triggering the Check Engine, but I noticed there was never any pressure excaping when I removed the gas cap. I checked the cap with my other car, it worked fine on that one, so elimiated the cap as a problem. Is there something that is a common or probable leak area on the s320 car. I understand there are many things that could cause a small leak, but not sure where to start looking. I did think about checking out the regeneration switchover valve, but have not taken the time to do that.

You seem very knowledgeable and wondered what your thoughts are on this issue?

Thanks again for all you help!
Harvey