Fuel pump relay differences

a4kcstq at comcast.net a4kcstq at comcast.net
Thu Feb 5 14:06:37 EST 2004

I just added a 5kt (MC) fuel pump relay to my 4kq about 2 weeks ago.
I think the relay uses 46 and 47 terminals to trigger, not the 46 and 1.  The 5kt relay doesn't have a rev limiter like the 4kq relay, so it doesn't use terminal 1 (rpm signal) to trigger.
The 5kt relay wants to get a ground signal through terminal 47 which should be 
connected to the ECU pin#21 (brown/grn wire).  In the 4000 fusebox, terminal 47 
is there, but it's not connected to anything underneath.
On the bottom side of the fusebox, locate the terminal "Bs" and connect this to 
pin#21 of the ECU.  That's all you have to do.
Unfortunately, locating the Bs terminal is hard.  I work from outside the car 
and pry up the fusebox plate.  Unfortunately, it doesn't pull out very far, so I had to use a flashlight and a small mechanic's mirror to read the terminals. 
There will be a row of large 8 pin connectors A through G, I think.  Find the B 
connector and it will have a blank spot labeled Bs.
With the 5kt relay, I also connected terminal 49 (1La underneath) to pin#31 of 
the ECU and the negative side of the check engine light.  That enables the fault code reading by inserting the spare fuse in the relay.
Hope this helps.

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