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01 C320 - "Dad, car dash is going crazy on me, all sorts of fault codes and rpm indicator bouncing up and down." Ok, dear, where are you. "High School parking lot." So, I leave work and meet her. ESP, BAS, Brake Lining, etc... Car has been flawless for 40K miles. Just replaced rear shocks, and front rear brake pads and sensors about 5K miles ago. What do you guys suspect here? I do not have any code readers for MBZ just Porsche. Should I just bite the bullet and take it to the stealer?
 

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First check the voltage - 12.5v at rest, no less than 11v during cranking, 14v at idle. Anything lower than that and I'd look at the battery or charging system.
 

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First check the voltage - 12.5v at rest, no less than 11v during cranking, 14v at idle. Anything lower than that and I'd look at the battery or charging system.
12.5 @ rest and 14.2VDC at idle. I assume then it is not a battery issue. Any other thoughts? Module, fusing, etc....?
 

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Maybe a bad instrument cluster, but try one more thing - assuming you have a spare key, see if that makes a difference.
 

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Maybe a bad instrument cluster, but try one more thing - assuming you have a spare key, see if that makes a difference.
Hi Rodney,
when I had a similar problem with c240, the instrument cluster was faded because it was really hot day. Do you think the faded screen could have caused the underpower issue and the P0720?

This happened rwo days after changing the brake pads when the P0720 malfunction code appeared and rhe vehicle sputterd but it has been driving normal since that incident and clearing the code.

The Haynes manual has two descriptions for P0720:

P0720: Electronic Transmission control (ETC) unit
P0720: Electronic Transmission control (ETC) unit. CAN message from rear wheels from ESP control unit missing or incorrect.

Are these descriptions basically saying the same thing?

Is it possible I may have affected the rear wheels/ ESP control unit while I was hammering the rotor to try to release it from the hub when I changed the brake pads? The rotor never released so I left it in place. Is there a diagram for how the ESP interacts with the rear wheels?

I appreciate your patience with with my inquiries.
 

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"I'm pregnant, and I'm not sure who the father is."

"Mom and I have run off with your retirement account."

"I think I put coolant in the oil thing and now the car just stopped on the freeway."

...

Always thought this thread had a funny title.
 

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The faded instrument cluster LCD panel will have no involvement with an engine error code. P0720 is a generic code that says there is an error in the traction control system . You'll need to get the ESP system scanned, an that will require a specialized tool like SDS or iCarsoft. Generic OBDII scanners won't do it. It's possible that working on the brakes, you damaged the wheel speed sensor, ot the wiring for it.
 

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OK I was able read these stored codes, in order, after several tries to "initilalize" the TRANSMISSION part of the icarsoft i980:

P2600 the voltage supply of circuit 87 has undervoltage

P2602 the voltage supply of the valves is faulty

P2315 one or more messages from control unit A1 (instrument cluster) are not available on the can bus

P2316 one or more messages from control unit N19 (Air Cond control unit) are not available on the CAN bus

P2310 one or more messages from control unit N47 (Traction Systems Control module) are not available on the CAN bus.

I couldn't read the ESP system codes because I get this message on the i980: "FAULT IN COMMUNICATION WITH VEHICLE ECU". I receieved the same message while trying to read the TRANSMISSION codes but after several tries I got it to initialize and was able to read the codes above. Are these codes related to the P0720 I got from the generic reader?

Should I start by looking at the Alternator first (the battery is a year old), hoping that's the source of the problem(s)?
 

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You very well may have a voltage (battery or alternator) issue. What's the voltage with the ignition switched on but the engine stopped? Should be at least 12.5v.
 

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You very well may have a voltage (battery or alternator) issue. What's the voltage with the ignition switched on but the engine stopped? Should be at least 12.5v.
just checked in Dyno mode, engine not running, 12.3 then goes up to 12.4v
Checked with digital multimeter I get 12.7 off and 14.3 running...seems normal!?
 

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That voltage is a bit low but not horrible. It looks like the alternator is putting out. I'd clear the errors and keep an eye on it.
 
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