Hello!
Sorry for the long post, but I figure the more information the better (might help someone some day).
ETM 8644345 white label died with an internal fault (ELM showed P0106) on V70 Bifuel CNG 2001 (B5244SG) manual. It got progressively worse with the limp mode, the usual stuff. The sensors showed 1.25...1.30V at default position, but the internal chip did not appear to respond to any commands. Instant limp mode whenever it is plugged in - even after disconnecting the battery for a while. (Btw, the car is in a pretty good condition under the hood. Only done 143k miles which looks to be correct. I think I was the last person on Earth with the white label that never got replaced under warranty.)
Hard to get the same one, so found a yellow label 864434
4 that had been taken from a pure petrol model (specifically, from a B5244S of the same year) that was claimed to work, and I also ordered a Sacer contactless TPS.
As it is (without doing anything to it), the replacement ETM does not throw any codes whatsoever (!), drives more or less fine on petrol, but idles high (1500rpm) on both petrol and CNG, and has trouble staying on CNG after driving for a while. ELM OBD2 reports 12% TPS reading at idle and 65% at WOT. The white label reported 20% at idle and over 80% on WOT.
So I have the replacement ETM on the table, and whenever I power it up via green (+12V) and brown (GND) wires, the actuator and the plate start quickly oscillating between a default value and a value very close to it (at a rate of about 3...6 Hz), as if it is unsure which way to go. (The white label ETM stayed silent on the table.) Cleaned up the TPS pins and they show 1.31V and 1.35V at default position for the 5-pin side and 3-pin side, respectively, which seems to be within range.
I think I will try to replace the yellow label's TPS with Sacer if I know the ETM is not 'internally' broken, and then let a shop update the firmware (don't yet know, ECM or ETM or both? calibration? every action they do costs quite a bit). The yellow label seems to be in a much better condition overall, and it seems to be a logical choice between the two since it's supposed to be version 2.
I'm worried about the oscillation behavior though - why would it oscillate like that? The lab power supply shows the module draining 260mA at 12.2V while doing this (max is set at 1A), and this current seems to account for the actuator oscillation. Has anyone ever experienced this? I haven't energized it for more than 10 seconds as not to burn something up, though I am pretty sure I've heard the same type of clicking in the car for a longer time, and I've driven it about 10 miles so far with the new ETM to the garage and back.
The yellow label also allows to move TPS with key in position II, with an audible buzz, whilst the white label did not allow it.
Some numerical results
Code:
Original white label 8644345 (instant limp mode)
Fully Closed Default WOT
3-pin side TPS 0.555V 1.253V 4.130V
5-pin side TPS 0.466V 1.200V 4.200V
Crossfeed 0.590V 1.358V 4.500V
Yellow label 8644344 (idles high, oscillates on the bench)
Default Fully Closed Default WOT
3-pin side TPS ? 1.35V ?
5-pin side TPS ? 1.31V ?
Yellow label behavior (high idle while the reported TPS% position is actually lower):