Can you help me identify what type of diode is in the ABS solenoid valve relay?

It is a "fat-barrel" type relay with the following markings:

BTW 56 PH

The "B" could be an "8"
The "T" could be a "Y"

It looks like this from the Radio Shack catalog:
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F006%5F000&product%5Fid=276%2D1141





Rather than replace with a similar diode, I was thinking about installing one with a higher forward current (6-amps?) and a higher Peak Inverse Voltage (PIV) of say 200-400 VDC, like those found here:

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F006%5F000&product%5Fid=276%2D1144

http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F002%5F006%5F000&product%5Fid=276%2D1143

However, I'm unsure of the current diode's ratings, and whether or upgrading is smart move.

The "flickering ABS" light is what started it all and below is the resolution.

PS: what is a "fast" or "ultra-fast" recovery diode vs. a "tunnel" diode, and under what applications is each best suited for?

Thanks in advance,

:-) neil
1988 360TE AMG
1993 500E
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I pulled the ABS solenoid valve relay (42-0710) (silver-colored "ice-cube" relay) and tested contacts 30 & 30C for a faulty diode.

Sure enough, bad diode, got a new relay for $33, and all is fine (MB pn# 001.542.6719).

I will try and open up the bad relay and install a new diode. . .

BTW: this relay is DIFFERENT than the other "ice-cube" silver relays which do NOT have a diode between contacts 30 & 30C.