Service Manual

Groundsmaster 4500−D/4700−D Page 3 − 5 Yanmar Diesel Engine

Engine Electronic Control Unit (ECU)

The Yanmar engine that powers your Groundsmaster

uses an electronic control unit (ECU) for engine man-

agement and also to communicate with the machine

TEC controllers and the operator Info Center display on

the machine. All wire harness electrical connectors

should be plugged into the ECU before the machine igni-

tion switch is moved from the OFF position to either the

ON or START position.

The engine electrical components (e.g. ECU, fuel inject-

ors, EGR, exhaust DPF) are identified and matched in

the engine ECU program. If engine electrical compon-

ents are replaced on the engine, the Yanmar electronic

tool must be used to update the ECU program which will

ensure correct engine operation.

If the engine ECU identifies that an engine problem ex-

ists, the engine speed may be reduced or the engine

might stop. The Yanmar electronic tool and

troubleshooting manual should be used to provide as-

sistance in identifying the cause of the problem and the

repairs that are necessary. Contact your Toro distributor

for assistance in Yanmar engine troubleshooting.

IMPORTANT: Do not plug or unplug the engine ECU

for a period of thirty (30) seconds after the machine

key switch is turned OFF. The ECU may remain ener-

gized even though the ignition switch is OFF.

If the engine ECU is to be disconnected for any reason,

make sure that the ignition switch is in the OFF position

with the key removed before disconnecting the engine

ECU. Also, to prevent possible ECU damage when

welding on the machine, disconnect and remove the en-

gine ECU from the machine before welding.

Figure 1

1. Engine (models 30873 and 30874)

2. Engine ECU

Figure 2

1. Engine (models 30881 and 30882)

2. Engine ECU

Yanmar

Diesel Engine