Common Failures with 272/273 Engines, ME97
Knowing these four pattern failures of the ME97 engine controller for the 272-273 engine can help expedite your diagnosis and avoid replacing the wrong parts.
In MY … the fuel pump relay control (Pin 17) can fail intermittently causing no start and stalling concerns.
If the ground near the ignition coil is left off after repairs and the engine is cranked, the ignition coil drivers for that entire bank can burn out. It has happened that quickly. Beckmann Technologies / Bluelink Diag can repair these and they may have reman or used units for the other failures.
The CKPS sensor up until about mid 2007 fails, especially when hot. You can measure continuity across it when heating it up and you may see it go open if the sensor is bad. (Not an ME failure, but worth noting here).
Lastly, the trifecta. If you get current codes for throttle, oxygen sensor, and alternator, and they come back when the key is cycled on, you're probably looking at a bad module. If you have another one around you can plug it in and turn the key, the faults will not reset. We've seen it on 164, 221, 203, 211, 204, 209, and 171 from at least 2005 to 2009. Attached are some quick tests showing the oxygen/throttle/alternator issue.
We can program and SCN Code a replacement module via a pass through device or via the RAP kit:
Note: This tip is for informational purposes only and is not a diagnosis for your specific vehicle.
I'd be interested to find out more about your passthrough programming and can coding. Do You do other modules?what is the cost associated with it. Good read btw
I've never run into it on a Mercedes but similar situation on BMW. If you're doing a valve cover/gasket and forget the ground wire at the cover and start it you are toast. You get oil level codes, BSD, and alternator codes. Order a new DME.
So Drewtech is now doing Mercedes or is it through Farsight? Are you able to do all modules on all years (OBD2)?
I have seen to O2 senor, alternator, and Throttle faults. I tried to go through BBA reman to get it repaired and after 3 attempts I was finally returned my customers money.
One note about this although it is a rare situation, it's possible to have the 1337 Alternator Serial Interface code without an alternator, wiring, or ME module problem on certain vehicles.
If the vehicle is California Emissions it may be equipped with a Premair sensor which monitors whether a special ozone reducing radiator is installed or not. The ME monitors the Premair sensor for circuit faults and also for rationality; it detects if the temperature of the radiator is following the expected performance of the cooling system.
That Premair sensor is connected to the alternator LIN inside the engine module (M272/ME97) and sometimes it shorts the LIN bus to voltage. A normal voltage reading for the LIN bus is generally 7-8 volts (officially it's 7.5-10) and this depends on whether the system voltage is from the alternator or the vehicle battery as the LIN voltage thresholds are set at a percentage of system voltage, not a specific voltage. A stable/incorrect voltage on the LIN wire is a tip off that the circuit has a fault but what you really want to do is unplug the Premair sensor and check if the alternator code goes away.
You can check the LIN voltage before and after disconnecting the Premair sensor for confirmation it is shorting the line. LIN voltage should not change dramatically as components are added and removed.
I have seen this a few times now and other technicians have seen it as well, sometimes the sensor or wiring is damaged in a collision. The other code you are likely to see together with 1337 is 1897 "The Premair Sensor has a Sporadic Malfunction"
Hope this helps