bench testing FD ECUs
bench testing FD ECUs
Thought I'd share in case anyone was traveling the same path. I had a couple of ECUs of unknown provenance and while just plugging them in would be the best indication of working, I wanted to be a little more cautious and test them on the bench first.
What you'll need..
Familiarize yourself with the ECU pinouts https://stocksray.com/ecupins.html
These are the pins when you are looking at the ECU - not the connector.
If you have a spare connector it's easier to get to the wires - otherwise you'll need to clip the pins in the ECU.
1) 12V power (through fuse) - goes to 1B. Please use a fuse just in case.
Note 1A is constant power but I think this is only so the ECU remembers settings. Seems not needed for this use case.
2) Ground to 4A, 4B, 4C.
3) Now connect the LED from +12V to 1F (FEN). LEDs are directional - you need to put the anode on the B+ side.
The documentation is a bit confusing - MEN 1D is often shown as the check engine lamp. An LED here will light up but won't blink.
4) Short TEN I1 to ground. This is the same as using the jumper in the diagnostic part to get the lights flashing.
5) Energize the circuit and if all goes well the LED will go on, go off then start cycling through the codes. It will dump dozens because of all the open circuits.Codes I saw ... 5,9,11,12,13,19,20,25,26,28,30,31,32,33,38,39,40,4 2,43,44,45,46,50,51,54,71,73
Note if you see code 14 - this indicates atmospheric pressure issues in the ECU. I'd be suspicious.
If the LED isn't blinking - confirm you've got a resistor in series. You can try reversing the leads in case it's backwards. If the LED stays solid - confirm you are on FEN 1F and not MEN 1D.
All the best!
What you'll need..
- 12V DC Power supply
- 2A fast blow inline fuse
- small alligator clips
- 12V LED with resistor.
Familiarize yourself with the ECU pinouts https://stocksray.com/ecupins.html
These are the pins when you are looking at the ECU - not the connector.
If you have a spare connector it's easier to get to the wires - otherwise you'll need to clip the pins in the ECU.
1) 12V power (through fuse) - goes to 1B. Please use a fuse just in case.
Note 1A is constant power but I think this is only so the ECU remembers settings. Seems not needed for this use case.
2) Ground to 4A, 4B, 4C.
3) Now connect the LED from +12V to 1F (FEN). LEDs are directional - you need to put the anode on the B+ side.
The documentation is a bit confusing - MEN 1D is often shown as the check engine lamp. An LED here will light up but won't blink.
4) Short TEN I1 to ground. This is the same as using the jumper in the diagnostic part to get the lights flashing.
5) Energize the circuit and if all goes well the LED will go on, go off then start cycling through the codes. It will dump dozens because of all the open circuits.Codes I saw ... 5,9,11,12,13,19,20,25,26,28,30,31,32,33,38,39,40,4 2,43,44,45,46,50,51,54,71,73
Note if you see code 14 - this indicates atmospheric pressure issues in the ECU. I'd be suspicious.
If the LED isn't blinking - confirm you've got a resistor in series. You can try reversing the leads in case it's backwards. If the LED stays solid - confirm you are on FEN 1F and not MEN 1D.
All the best!
Thanks for the idea! The same basic approach, but with obviously different pin #'s, should work as well on USDM S5 & S4 FC's. Just need to hit up the FSM/wiring diagram to get the correct pin #'s. Now I can find out if any of those questionable FC ECUs I have laying around my basement are still useful!
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JoelosFD3S
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Aug 14, 2019 11:25 PM