New York inspection connected the computer to get the emissions report and would not read

Tiny
LANDRTHEGREAT
  • MEMBER
  • 2005 MERCEDES BENZ C240
  • 2.6L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 50,000 MILES
Took my car listed above (W203) 4Matic Sedan to get a New York inspection. They connected the computer to get the emissions report and would not read. I took the car home and looked up what the drive cycles were that were required to get the readings but nothing would show up. Checked with my OBD2 and got the message "No Power-train DTCs or Freeze Frame Data presently stored in the vehicles computer."I have put 1,500 miles on since then and re-tried (completed several drive cycles) with the same turn out. Did some testing on the OBD port on the car  - no power to pin 7 (K-line), resistance on 4 -.5, resistance on 5 - 0.0, resistance on 7 -21.3.  Do you know where power for K line comes from? I checked all the fuses and found no issues. Vehicle VIN is WDBRF81J55F613276. Using iCarsoft Multi-system Scanner i980. - No problem reading other systems only issue is with emissions.  No codes related to CAN or BUS or any computer system.  Only code I get is B1066 - Roof system is not normalized. Purchased a used computer for the car but do not have anyone nearby that can program it for me.I cannot get the car inspected so I will not even be able to renew my registration. Any suggestions would be greatly appreciated.    
Car runs perfect.  No warning lights.  Just need inspection.
I was considering replacing the ECU, but did not want to spend any more money before I figured out what the problem is.
Friday, November 15th, 2019 AT 11:24 AM

1 Reply

Tiny
STEVE W.
  • MECHANIC
  • 13,452 POSTS
There won't be power on the BUS lines, they are only signal lines. Pin 7 goes directly to the ECU. I would see if you can get an oscilloscope somewhere and use it to read that data lines at the DLC and then go to connectors and pins shown on the diagram and see if you have the same signal at the ECU pins by backprobing the ECU connections. If you cannot get a scope you can at least use the diagram to test continuity from the ECU side to the DLC. I wouldn't swap the ECU until you are sure it isn't just a bad connection at the ECU or a bad wire.
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Friday, November 15th, 2019 AT 3:35 PM

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