Roberte01

New-to me ML350, 58K miles, last 8 of the VIN is AA608959. I bought it at a Lexus dealer, 'AS-IS' (My favorite window sticker....). Everything checks out clean, drives fine, no lights on, paint metering checks out. On the way home from the dealer, the gas gauge suddenly drops to zero, Pull codes, 2228 and 2229, 'the left fuel level sensor has an electrical fault' Fine, get a replacement left fuel filer/level sensor, pull the enormous PITA body panels over both the left and right sides of the tank, R&R the filter/level sender, all good. To R&R the left sender you have to remove the right side fuel pump/level sender to connect the crossover hose. Which means you have to remove the gaggle of modules that live above the fuel pump, including the rear SAM:



So I had to R&R the rear SAM to do the fuel level sender work. Fast forward a couple of days, I try to open the rear hatch with the key fob. It'll make the noise, the hatch will move 1/4" but not release. I can open the hatch using the manual override. Fuse 40 is good, since it's getting power. Pull codes again:



Ok, these rear hatch locks are problematic, I replaced the latch with one of the Uro parts units, 164 740 05 00 (EPC says the part number after chassis 532751 is 164 740 06 35, the parts supplier said that 164 740 05 00 is correct for this application) . I had to drill out one of the rivets to the inner manual latch mechanism to get the latch out and back in. Button everything up, but no joy- It'll actuate and make the noise but no movement. And now the button for closing the liftgate isn't lighting up. And the inner manual latch release isn't working. (Note- you CAN remove the rear hatch trim from an ML350 with the hatch closed. It isn't much fun, but it can be done. Turns out I didn't seat the cable in the manual latch release properly..

Anyway- Pull codes again, still have the three open circuit lines between the latch and connector F on the rear SAM. I check the wiring harness and the F connector at the rear SAM, no obvious breaks, pinches, etc. (I did not continuity test those three wires, which is probably the next step, to confirm...)



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So- the obvious next step is making sure there's continuity on those three connections at the rear SAM. But if the wires check out (and I think they will), where to go next? I did not adjust the 'loop' that the latch hooks onto, I did not 'denormalize and renormalize' the rear door closing (I think this means resetting the full 'swing' of the door opening range?)

Maybe I cooked something in the rear SAM? Battery was disconnected for all of the fuel and rear hatch latch work. Anyone seen this particular set of error codes related to the rear hatch latch?

Roberte01

Today the code 90D2 reappeared (rear door locking unit is defective), along with a warning notice on the dash that the rear hatch isn't latched and a 3rd brake light warning, which are new. I'm thinking the rear SAM is unhappy. Ordered one from FCP Euro.

Roberte01

Followup- It was something I did. Installed the replacement rear SAM without realizing that I do not have the ability to code a new rear SAM with my Xentry unit, so I ended up putting the old rear SAM back in to prepare for getting the old coding read and transferred to the new one. After reinstalling the old unit all the error codes disappeared and the fuel gauge and motorized rear hatch work as they're supposed to.

I must have incompletely seated the 'F' connector on the rear SAM while doing the fuel level sender R&R. And now I have a back-up rear SAM for when the original actually fails...