Nilfisk-Advance 56507009, Troubleshooting Manual

Page: 27 / 82

FORM NO. 56043129 - SR 1900 - 27
ENGINE SYSTEM
TROUBLESHOOTING GUIDE
Troubleshooting Guide
Symptom
4 cylinder 1.6 GM engine will not run at high speed
Note: With the engine running at idle press the engine speed switch to activate the high speed
engine function..
1.6 GM engine will not
run at high speed
Test the continuity of
the throttle input wire
Gra/Blu from the ECM
to the A2 control box.
Repair if faulty .Does
engine run @ high
speed ?
Test the speed SW.
input to the A2 control
box by cycling it On &
Off, checking the (*)
ribbon connector
ground input
(continuity) pins J3-1 &
J3-4.
If speed switch checks
open or closed all the
time replace the
membrane switch
panel assembly.
Does speed SW test
ok?
No No
Substitute a good
known working ECM if
engine runs properly
@ both idle & high
speed replace ECM.
Substitute a good
known working A2
control box if engine
runs properly @ both
idle & high speed
replace A2 control box.
Yes
* Ribbon connector see Electrical System Figure 1 for detail pin call-outs.
Press the speed select
switch on the operator
panel. Cycling it On &
Off test for 12V @ the
engine ECM pin# 51
wire Gra/Blu to Battery
Grnd.
• 0 volts engine will
only run @ idle.
• 12 volts engine will
run @ high speed
Is there 12V @ the
ECM throttle input but
no H.S. engine
operation?
Yes