Thread: ECM fried?
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Old 03-31-2021, 03:17 PM   #10
Chuma87
Scooby Newbie
 
Member#: 470383
Join Date: Jul 2017
Chapter/Region: International
Location: Argentina
Vehicle:
2002 Forester S-Turb
Grey

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If the IC is burned out, how is it physically? because I didn't see anything on the ECM board that is burned out ...

Quote:
Check the voltage on the pin while the load is disconnected and the pump is supposed to be running..
You mean...key switched to ON, check the voltage on GND signal (B136 pin#16)....With the FP relay connected/plugged:
Quote:
B46 connector with relay plugged.
-Searching GND signal from ECM.
Multimeter on continuity, black multimeter lead on chassis, red multimeter lead on ECM signal, key switched to ON...NOTHING
Multimeter on continuity, red multimeter lead on chassis, black multimeter lead on ECM signal, always "piiiiiiiiiiiiiiiiiiiiiiiiiiiii" (found GND) whitout switch key to ON.
-Searching V from ECM (low Voltage)
Multimeter on "20v", black multimeter lead on chassis, red multimeter lead on ECM signal, key switched to ON...12~12.2v found on that pin.
With the FP relay disconnected/unplugged...what I quote below:
Quote:
B46 connector with relay unplugged.
-Searching GND signal from ECM.
Multimeter on continuity, black multimeter lead on chassis, red multimeter lead on ECM signal, key switched to ON...NOTHING
Multimeter on continuity, red multimeter lead on chassis, black multimeter lead on ECM signal, key switched to ON...2 seconds of "piiiiiiiiiii" from multimer = found GND signal from ECU.
-Searching V from ECM (low Voltage)
Multimeter on "20v", black multimeter lead on chassis, red multimeter lead on ECM signal, key switched to ON...4~4.5v found on that pin.
Quote:
Originally Posted by Cougar4 View Post
Your connections shown in the drawings to the relay are wrong, if that is the way you have things wired. If battery power is tied to pin 30 then the FP power lead needs to be connected to pin 87, or 87a if 87 is the normally closed contact connection. I think 87a is the normally closed position (connection to pin 30 when the relay is OFF). Pin 87 and 87a work oppositely from each other and pin 30 is common to both pins, but only one pin is tied to 30 at a time, depending if the relay is either off, or on. Pin 86 would tie to switched power and pin 85 would tie the ECU lead that controls the relay operation, which makes a connection to ground to turn on the relay.
From the picture, the two connections with the alternative relay (A or B), are the ones that I used and that may have been the ones that caused the current failure of the car. After that, I went back to the original relay and it doesn't work. But if I get the GND from the chassis, it works,



Is it possible that the GND is "weak" and that is why the 12v passes?
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Last edited by Chuma87; 04-01-2021 at 07:42 AM.
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