Subsection of GenBoard/VerThree/Testing
Only disassemble an ECU if really needed. Many tests can be done by measurement (with the help of VemsTune output menus, test mode=ON).
For some operations it's enough to remove endplate only. Typically the following subcircuits can be reached through the endplate:
- including the MAT pullup resistor (which can be piggybacked 2700 x 510 = 430 Ohm for AAN / 3B factory PTC)
In rare cases, if disassembly is justified
If you unclamp the TO220 FETs, and disassemble the ECU, assemble with care:
make absolutely sure that insulatorsheet is undamaged and neighbor FETs don't touch.
When ECU unpowered (or even disconnected from the harness, measurement can be done with a few econoseal pins or alligator clips), injector outputs should NOT be connected to any other injector output.
Verify this with DVM diode or beep mode measurement.
This would be 8*7/2 = 28 measurements if done naively (or actually 36 to also measure connectivity to case: which is also NOT desired).
Knowing neighbor traces, the official procedure, with a small trick: EC36/21 + case preconnected it's only 15 measurements:
EC36/6 .. EC36/17 EC36/6 .. EC36/18 EC36/6 .. case + EC36/21 EC36/7 .. EC36/18 EC36/7 .. EC36/19 EC36/7 .. case + EC36/21 EC36/8 .. EC36/19 EC36/8 .. EC36/20 EC36/8 .. case + EC36/21 EC36/9 .. EC36/20 EC36/9 .. case + EC36/21 EC36/17 .. case + EC36/21 EC36/18 .. case + EC36/21 EC36/19 .. case + EC36/21 EC36/20 .. case + EC36/21
Measure with DVM diode or resistane (2kOhm) mode: there should be NO connectivity
- Beeping or <300 mV or <300 Ohm shows short / connectivity => bad