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I have decided to start this thread to understand the EJ25 wiring loom a bit better and hopefully it will be of help to some others in the future. I had a 2.5 SOCH EJ25 installed in my van and now I want to make sense of it all. I bought the engine from a good source, it had already been in a T3 van so I did not have the engine loom done and I'm not 100% sure who did it, hence the need to understand it better, I may want cruise control etc in the future. I've taken a load of photos and I'm hoping people can help me to identify the various parts and I can then E D I T the main page with the correct information.
------------------------ A - This is the only loom info that came with my engine
B - Dashboard end of the 7 core trailer cable (red, green & black connected to the speed sensor plug)
C - Plug that connected the 7 core cable to the subaru loom
D - Subaru loom end
E - 7 core cable end
F - OBD2 diagnostic socket
G - ECU & Key
H - ECU Label
I - Subaru Immobliser
J - Green Fuel Pump Relay & the Brown Ignition Relay
K - Connect for Diagnostic Mode, testing relays, fans, dash lights. Disconnect when not testing.- Slowcoach informed me thatsimilar black plugs are to display check engine light (CEL) codes. Both activate when ignition power is on (engine does not need to start). plenty of info on the green and black plugs are online though, and referred to as the green plugs
L - 2 x 10a fuses - dont know what they are fusing
P - Two lambda probes (connected to Dai's exhaust) - 2nd one is usually after the CAT, not fitted on our van conversions. ECU still needs two readings, before and after.
Q - Plug end of the sensors
R - Not sure what these plugs are for
S - ....or these plugs
T - Engine Bay
Last edited by irishkeet on 12 Oct 2016, 15:09, edited 5 times in total.
irishkeet wrote:
P - Two probes connected to Dai's exhaust - one is the lambda Sensor - what is the other & which is which
ill answer a simpler one, since im no expert yet on my own wiring, but theyre both lambda probes, the second one is usually after the CAT, not fitted on our van conversions. that ecu still needs two readings, before and after.
the two green matching plugs are part of the diagnostics- you might have 2 black ones very similar too- i connect both black together for displaying 'check engine light' codes. Both greens together is for diagnostics checking of relays etc - both connected and ignition on will cycle the fuel pump and ignition relays, rad fan, and some other things!
slowcoach wrote:
ill answer a simpler one, since im no expert yet on my own wiring, but theyre both lambda probes, the second one is usually after the CAT, not fitted on our van conversions. that ecu still needs two readings, before and after. - updated -
the two green matching plugs are part of the diagnostics- you might have 2 black ones very similar too- i connect both black together for displaying 'check engine light' codes. Both greens together is for diagnostics checking of relays etc - both connected and ignition on will cycle the fuel pump and ignition relays, rad fan, and some other things!
should they only be connected for diagnostics, what are you using to connect to your engine Slowcoach?
slowcoach wrote:
ill answer a simpler one, since im no expert yet on my own wiring, but theyre both lambda probes, the second one is usually after the CAT, not fitted on our van conversions. that ecu still needs two readings, before and after.
the two green matching plugs are part of the diagnostics- you might have 2 black ones very similar too- i connect both black together for displaying 'check engine light' codes. Both greens together is for diagnostics checking of relays etc - both connected and ignition on will cycle the fuel pump and ignition relays, rad fan, and some other things!
should they only be connected for diagnostics, what are you using to connect to your engine Slowcoach?
Correct- greens are only connected for diagnostics, and when flashing the ecu as I understand? Leave disconnected all other times.
I can't attach a code reader to mine ('99 forester), if that's what you mean- I don't have odb2, and it's not a recognisable common protocol, I've been told. Syncroandy knows more on that! Though I do have a plug that looks like the obd2 one :-\ I just connect the black diagnostic plugs together to flash me the codes on the led. Left disconnected all other times..
I bought the engine from a good source, it had already been in a T3 van so I did not have the engine loom done and I'm not 100% sure who did it, hence the need to understand it better, I may want cruise control etc in the future. I've taken a load of photos and I'm hoping people can help me to identify the various parts and I can then E D I T the main page with the correct information.
- updated - 