B&M 120001 SHIFT PLUS 2 TRANS CONTROLLER - Manual (Page 4)

TCC APPLY (grey wire)
When switched to ground, (and when some very basic requirements are met) this TCU input forces the torque
converter clutch to lock up. Otherwise, the TCC will lock and unlock automatically based on user configurable
settings.
FLASH ENABLE (blue wire)
This wire is only used in the rare case that new firmware needs to be loaded into the TCU. This wire would be
grounded as the TCU is keyed on. Be sure that this wire is not accidentally grounded in normal operation. If the TCU
accidentally starts up in Flash Mode (LED flashing steady on/off pattern – a slower pattern than the rapid flashing
that indicates an error code has been set), the transmission will not function properly. If that occurs, make sure the
FLASH ENABLE wire is not grounded, then key off, wait about 10 seconds and key back on.
HANDHELD
This connects to the communications cable that links the main wiring harness to the handheld user interface.
SPEEDOMETER CONTROL UNIT
This connects to an optional B&M Speedometer Control Unit (SCU) (part# 120004). A SCU uses an electric motor to
spin a special speedometer cable to drive a mechanical speedometer.
RPM MODULE:
There are two basic options for supplying the Shift Plus 2 with an RPM input.
1. Clean, processed Tach signal from engine electronics
Electronics involved in running the engine – fuel injection, ignition, etc. – will need to know engine RPM. So there
may be an existing tach signal wire that can be tapped into. The Shift Plus 2 requires a square wave type tach
signal that pulses once per cylinder firing. Ignition systems – such as aftermarket capacitive discharge (CD) ignition
boxes – often have dedicated “Tach” outputs that are a perfect RPM signal source for the TCU.
If using a clean, processed Tach signal, the TACH IN / RPM MODULE wire in the Shift Plus 2 wiring harness is
connected directly to that source - the “Tach” output from an ignition box, etc. The RPM Module included with the kit
is not used in this case and no part of the Shift Plus 2 system is connected to the coil.
2. Inductive coil
Another RPM signal source is the negative side of the ignition coil in a traditional dwell controlled inductive ignition
system. One in which the coil is fed power on one side and is charged by grounding the other side - either by
“points” or some form of electronic module. An HEI is one example of this type of ignition system.
To use this RPM signal option, the RPM Module is required. The RPM Module connects to the negative side of the
coil and outputs a “Tach” signal to the TCU. The RPM Module is connected as follows:
Wire color Connection
Black Engine block
Black Engine block
White Negative side of coil
Yellow TACH IN / RPM MODULE wire in the Shift Plus 2 wiring harness
The RPM Module is provided to allow this convenient installation option. But keep in mind that it has limitations.
The negative side of an ignition coil is one of the noisiest points on the engine. In most applications, the RPM
Module will be able to deal with this and feed a clean RPM signal to the TCU. But the old saying – garbage in,
garbage out - applies here. If the inductive ignition system is just too noisy or inconsistent, a different RPM signal
source will be needed. A poor RPM signal can cause the RPM display on the Live Data screen to appear erratic. It
can also lead to inconsistent shift points under heavy load.
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