Standard Control Module (Scm) - Toro 30849 Operator's Manual

Figure 26
1. Bypass valve
2. Before starting the engine, close the bypass valve by
rotating it 90° (1/4 turn). Do not start the engine
when the valve is open.
Standard Control Module
(SCM)
The Standard Control Module is a potted electronic
device produced in a one size fits all configuration. The
module uses solid state and mechanical components
to monitor and control standard electrical features
required for safe product operation.
The module monitors inputs including neutral, parking
brake, PTO, start, backlap, and high temperature. The
module energizes outputs including PTO, Starter, and
ETR (energize to run) solenoid.
Here are the logical troubleshooting steps for the SCM
device.
1. Determine the output fault you are trying to resolve
(PTO, START, or ETR).
The module is divided into inputs and outputs. Inputs
and outputs are identified by green LED indicators
mounted on the printed circuit board.
The start circuit input is energized by 12 VDC. All
other inputs are energized when the circuit is closed to
ground. Each input has a LED that is illuminated when
the specific circuit is energized. Use the input LED's
for switch and input circuit troubleshooting.
Output circuits are energized by an appropriate set of
input conditions. The three outputs include PTO, ETR,
and START. Output LED's monitor relay condition
indicating the presence of voltage at one of three
specific output terminals.
Output circuits do not determine output device
integrity so electrical troubleshooting includes output
LED inspection and conventional device and wire
harness integrity testing. Measure disconnected
component impedance, impedance through wire
harness (disconnect at SCM), or by temporarily "test
energizing" the specific component.
The SCM does not connect to an external computer or
hand held device, can not be re–programmed, and does
not record intermittent fault troubleshooting data.
The decal on the SCM only includes symbols. Three
LED output symbols are shown in the output box. All
other LED's are inputs. The chart below identifies the
symbols.
Figure 27
2. Move key switch to the On position and ensure that
the red power LED is illuminated.
3. Move all input switches to ensure all LED's change
state.
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