SEAT Ibiza AQX/AYP 20v -> CE2 + general fusebox plug reference guide

Hello all, since this has been asked a few times now I'll paste in the details I have noted down on these looms. It's only got CE2 splicing info for the main ecu plugs currently, but you should be able to work out CE1 splicing from my other OEM MK4->MK1/2/3 guide here:
https://clubgti.com/forums/index.php?threads/267196

Engine loom plugs:
T28 - big round plug on sensor loom:
1 - crank sensor pin 3 - ECU pin 82
2 - crank sensor pin 1 - ECU pin 108
3 - fuel injector #4 pin 2 - ECU pin 88
4 - fuel injector #2 pin 2 - ECU pin 89
5 - crank sensor pin 2 - ECU pin 90
6 - oil pressure switch - G2/10 or G2/11, or ignore and run own wires for pressure switches
7 - coilpack #4 pin 3 - ECU pin 94
8 - coilpack earths - battery negative
9 - coilpack #2 pin 3 - ECU pin 95
10 - fuel injector #1 pin 2 - ECU pin 96
11 - fuel injector #3 pin 2 - ECU pin 97
12 - knock sensor 2 pin 3 - ECU pin 108
13 - knock sensor 1 pin 2 - ECU pin 99
14 - coilpack #1 pin 3 - ECU pin 102
15 - coilpack #3 pin 3 - ECU pin 103
16 - knock sensor 1 pin 3 - ECU pin 108
17 - coil live feed - see ecu relay notes
18 - knock sensor 2 pin 1 - ECU pin 106
19 - knock sensor 1 pin 1 - ECU pin 107
20 - ECU sensor earth - ECU pin 108
21 - throttle body pin 6 - ECU pin 91
22 - throttle body pin 5 - ECU pin 118
23 - throttle body pin 4 - ECU pin 84
24 - throttle body pin 3 - ECU pin 117
25 - throttle body pin 2 - ECU pin 83
26 - fuel injectors pin 1 - Z/1
27 - throttle body pin 1 - ECU pin 92
28 - N249 pin 2 - ECU pin 9

T14a - smaller 14 pin plug on sensor loom:
1 - fuel pump power for engine loom - G1/8
2 - N112 valve pin 2 - ECU pin 105
3 - N75 pin 2 - ECU pin 104
4 - cam sensor pin 2 - ECU pin 86
5 - ECU temp sender - ECU pin 93
6 - dash temp sender - G2/3 (see coolant sensor notes)
7 - PAS switch pin 1 - ECU pin 49
8 - PAS switch pin 2 - ECU pin 50
9 - earth for dash temp sender - earth to head or battery negative
10 - speedo sensor pin 1 - G2/4 if using
11 - speedo sensor pin 2 - G1/11 if using
12 - speedo sensor pin 3 - earth if using
13 - inlet temp sensor pin 1 - ECU pin 85
14 - cam sensor pin 1 - ECU pin 98


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Internal wiring loom plugs:

T5g brown:
1 - blk/yel- ECU pin 41 - bin (radiator fan control unit pin T14b/2)
2 - grn/blk - ECU pin 40 - bin (aircon)
3 - pur/wht - ECU pin 41 - bin (radiator fan control unit pin T14b/3)
4 - gry/red - ECU pin 37 - G1/12, via tacho adaptor if mk2 (clocks pin T32/11, rev counter)

T5q:
2 - org/blk - can-bus high - bin (abs ECU)
3 - org/brn - can-bus low - bin (abs ECU)

T6f: (fuel pump relay, on relay plate)
1 - blk - bin (fuel relay main live from battery)
2 - red/blk - bin (fuel relay power to T10h for internal car fuses)
3 - blk/grn - bin (fuel relay ignition live)
5 - grn/wht - ECU pin 65 - G1/3 (fuel relay trigger)

T6h: (SAI relay, on relay plate)
1 - blk - bin (SAI relay main live from battery)
2 - red/blk - bin (power feed to SAI pump)
3 - red/yel - bin (pump power feed)
4 - grn/brn - ECU pin 66 - bin (SAI relay trigger)

T10d black:
1 - red/black - bin or swap to your loom (starter motor)

T10e white:
10 - gry/grn - ECU pin 43 - to vagcom diagnostics port pin 7 (clocks pin T32a/28, diagnostics)

T10f brown:
3 - pur - ECU pin 81 - to clocks if mk3 or newer, or bin (clocks pin T32a/1, mpg signal)
6 - blk/blu - ECU pin 30 - bin (clocks pin T32a/23 ???)
9 - wht/blu - speedometer sender - G1/11 if using, or bin
10 - wht/yel - ECU pin 54 - W/1 (VSS feed from clocks)

T10g green:
2 - yel - T26/6 - G2/10 or G2/11, or ignore and run own wires for pressure switches (oil pressure switch)
3 - grn/blk - ECU pin 37 (clocks pin T32/11, rev counter)
4 - red/blk - ECU pin 56 - tap to brake light switch red/black if using brake switch, or bin (brake lights ON)
6 - brn - coolant temp sensor earth (dash sensor common ground)
7 - red/yel - various engine electrics - G1/8 (fuel relay live, fuse 8)
8 - blk - T10g/9 - bin (ignition live, from ignition switch)
9 - blk - fuse 3 input - bin (ignition live, from ignition switch)
10 - blk/red - clutch & brake switches, speedometer sender - G2/4 if using any of these, or bin (ignition live, fuse 3)

T10h purple:
1 - grn/wht - ECU pin 48 - bin (clocks pin T32/13, EPC fault lamp)
2 - blk/yel - fuel relay - bin (ignition live, fuse 1)
4 - red/blk - bin (fuel relay power to internal car fuses)
5 - blk/grn - ECU pin 3 & T10h/7 - see ECU relay notes (ECU power, fuse 1)
7 - blk/wht - crash cut-off relay - bin (ignition live, fuse 1)
8 - red/wht - ECU pin 62 - G2/9 or Y spade (permanent live, fuse 2)
10 - red/grn - ECU pin 47 - bin (clocks pin T32/32, emissions fault lamp)

T10i red:
3 - brn/wht - brake light switch - tap brake light switch red/yellow if using brake switch, or bin (permanent live, fuse 20)
8 - blk/grn - T28/17 - see ECU relay notes (coilpack power, fuse 4)
9 - blu/yel - coolant temp sensor - G2/3
10 - blu - alternator pin D+ - tap to your old alternator blue wire


Coolant temp sensor notes:
The MK4 type 4 pin coolant temp sensor will not work correctly with MK1/2/3 clocks, but there are a few ways round this:
1. Fit a 39ohm resistor (33ohm previously suggested, but have reports that 39 works better) inline with the T14a plug pin 6 wire. I've heard mixed results from this, some say all is well but the time I tried it the gauge didn't work at all till it was removed

2. Fit a MK3 golf 1.8-2.0 8v 4 pin coolant temp sensor part number 357919501A or 6U0919501B, splicing the matching plug part number 357919754 to suit if necessary. This is my personal choice it works fine with the MK4 ECU and MK1/2/3 dash no resistors are required! However if you need to splice the early plug onto a late loom the pin numbers differ.

MK3 sensor pins:
1 - brn/blu - ECU sensor earth
2 - brn - dash sensor earth
3 - blu - ECU sensor feed
4 - yel/red - dash sensor feed

SEAT sensor pins:
1 - blu/yel - dash sensor feed
2 - brn - dash sensor earth
3 - blu - ECU sensor feed
4 - brn - ECU sensor earth

3. Fit a MK4 upper rad hose with sensor fitting 1J0121087 and add a MK2 golf 2 pin black coolant temp sensor, splice MK1/2/3 dash feed to one of the pins and earth the other pin:


ECU relay notes:
To be safe I would recommend you power the ECU and coilpacks from a relay and fuse. Ideally mount your ECU relay & fuse above the fusebox with nice clip on relay holders pinched from VW/SEAT in the scrappy, or buy new ones from VW using the part numbers below. I would run a 15a fuse inline with the power input to pin 30, the DBW looms are prone to cracking up on the coilpack wiring so best bet to be 100% safe. You may as well pop the ECU pin 62 permanent live from T10h/8 in with the relay perm live, put it after the fuse so its also protected.

ECU/coilpack relay wiring:
30 - permanent live - Y spade via 15a fuse
85 - earth
86 - ignition live - G1/4, G2/4 or D/8, 9 or 11
87 - power to ECU & coilpacks

MK4 Diagnostics port wiring:
1 - black/blue - ignition live
4 - brown - earth
5 - brown - earth
6 - orange/black - CAN BUS high
7 - grey/white - Diagnostics K line
14 - orange/brown - CAN BUS low
16 - red/white - permanent live

Note all you need for basic diagnostics with VAG-COM/VCDS is live, earth and K line wires to pins 16, 4 and 7 though.

VW Fuse and relay holder part numbers:
161937501/1H0937530 - fuse holder - 2.94+VAT
161937501b - relay holder for 6.3mm spades (i.e. most switched relays) - 5.39+VAT
867937501 - relay holder for 9.53mm spades (i.e. fuel pump and glow plug relays) - 4.11+VAT
357937501 - double relay holder for 6.3mm spades - 4.89+VAT

 

Thats your diagnostics wire so you want that, 'to vagcom port'. You want to put it to pin 7, will update the post to make this a little more clear Then give the port pin 4 earth and pin 16 live then its sorted

in brackets I'm just showing its original location, in case its useful for anyone diagnosing a 20v still actually installed in its original donor car for a change

 

I've got the grey wirte from ABS control unit pin 7 thru T10j/2, then vagcom port? But yes that wire is the ABS unit diagnostics wire so you dont need that unless you plan to install the ABS system. If you do, put both that pin and ecu pin 43 to the vagcom port pin 7.

If you want an OEM way grab yourself a MK3 Golf port and diagnostics jumper block, then you splice the mk3 jumper lines to the ecu and abs wires, that way you can build your ecu loom seperate to the abs loom same as VW did for MK2/3 golf

 

thats the one yep, sort of thing I'd pinch out of a mk3 in a scrapyard, post-96 all have these.

part number for this is 1H0972559A, and you want 1h0972791a or 1h0972701 for the jumper plugs with micro timer pins

 

the 31 relay will only work if its triggered by a thermoswitch on the engine somewhere so you'll have to add that. probably easier to add a basic timer relay, this is what Audi A3 used

run the ABS module direct to the battery, this is what MK3/Corrado/MK4 golf do. If you dont want to use a mk4 style battery fusebox fit some inline fuses on the ABS pump wiring and attach direct to the battery terminal. Go on a scrappy hunt and find a MK3 golf then nick its battery cables, much better terminal design than mk2. At the fusebox side its the Y spades you're lookign at for lives, but since even the mk3/corrado didnt run the ABS from there I wouldnt advise it.

reverse switch wiring is correct.

with brake switch you can tap it to the mk2 switch red/black on E/3 or use W/4. But only do this if you're wiring in both ECU brake switch wires to a 4 pin brake light switch from ibiza/mk4/etc, otherwise leave this disconnected and short the cruise switch white/yellow wire to ECU pin 55 to ignition live so ECU doesn't get confused with a brake pedal switch miss-matched state.

 

sorry I didnt reply to your earlier post I missed it somehow. looked at the ABS diagram and fleshed out the T10j plug:
1 - blk/wht - TCS/ESP button pin 6 (x-relay live, fuse 18)
2 - gry/wht - ABS unit pin 39 (diagnostics k-line)
8 - gry/red - ABS unit pin 22 (ABS warning light?)
10 - gry/grn - TCS/ESP button pin 1 (ABS unit pin 24, Cluster pin T32a/19)

so yeah T10J pin 1 to W/3. pin 8 you could use W/2 then pick up the feed on X/8 to your warning light wiring. pin 10 you coudl run to your own light somewhere or to W/5 -> X/7 or W/6 -> X/5 and add your own bulb to the MK2 warning light bar

you need a 109 relay if you want to put an ECU triggered relay in slot 3, these are not too expensive new from ebay/vw or whatever as MK4 still use them in the diesel engines. If you want to put an ecu triggered relay in a relay holder somewhere else then you can use pretty much any 4 pin relay you like, just loop the 30 and 15 pins to live 98 is your output and pin 85 to the ecu trigger. this is how MK4 AUM/AUQ/R32/etc 428 ECU are wired from the factory

I dont see why you couldn't use a 20a thermal fuse so long as your wiring is rated above 20a, if in doubt swap a normal 15a fuse in it. The terminals in the fuse holder are the same as used in normal fuse holders so if you get hold of a normal one later on down the line you can swap it right over

 

yes thats right, in the long term I wouldn't want to risk running a set of 4 coilpacks and ecu power from G1/10 as we have no data to tell us what kind of load this pin can take, plus on the DBW MK4 this feed comes into the sensor loom using a larger standard timer pin so this suggests VW didnt think junior/power timer were man enough. You could use the ECU relay socket for just your ECU power/switched live pin no problem, just use a 30 relay for that.

if you mount above the fusebox you can use a 109 relay or any 4 terminal switched relay whatever works for you. just be aware that the 17, 18, 100, 428, 67, 80 & 167 relay have larger terminals on the live and output pins so you need a different kind of relay socket vs if you use a 109 or 53 relay

 

and not a solder joint to be seen, lovely

the 31 relay is for rad fan after-run, the T wire went off to a thermo switch on the carb. If you get hold of a suitable thermoswitch you could re-purpose it as a turbo timer if you like

 

31 switches on the fan when the ignition is off, if the thermoswitch switches to earth

the mk2 yellow collar one listed as 100 degrees, not sure what temp to switch it off, maybe its printed on the side? theres a blue collar one for G60 which is 90 degrees.

so if need be you swap the thermoswitch for one which matches your needs and fit it where is appropriate. the red/white wire from relay pin 87 hangs around near the radiator fan, its a spade connection which plughs into the fan loom. so you simply unplug that, and run it to your coolant pump and give the pump earth. or leave it plugged in and tap the electric pump to the red/white wire if you want fan and pump together. this means the pump will run when the fan is triggered by the radiator thermoswitch, you could put a diode between the thermoswitch and the pump wire to stop that.

changing fan thermoswitch will mean the fan comes on a bit earlier than it should, but as long as the thermostat is ok it wont affect engine cooling. the problem with using this for your turbo timer is it will only work when the thermostat is open

 

hello there, use the G4aumauqecu wiring diagram, this has all the cruise control stalk pins covered