Manitowoc Grove CD3340B Service Manual page 173

CD3340B/YB4411
Finding Electrical Problems
It is possible to carry out a large portion of the ECU
diagnostics with basic workshop tools, such as a test lamp
and/or voltmeter.
NOTE: Never check for voltage directly across any pins on
the ECU. Internal damage can result from shorting
pins.
Checking Solenoid Operation
Forward 1st
Forward 2nd
Forward 3rd
Forward 4th
Reverse 1st
Reverse 2nd.
Reverse 3rd
Reverse 4th
A0797
RH Reverse High MS Main Shaft
FL Forward Low
LS Layshaft
GROVE
Solenoids Figure 7-9
Forward Low (FL) and
Layshaft (LS)
Forward High (FH) and
Layshaft (LS)
Forward Low (FL) and
Mainshaft (MS)
Forward High (FH) and
Mainshaft (MS)
Reverse Low (RL) and
Layshaft (LS)
Reverse High (RH) and
Layshaft (LS)
Reverse Low (RL) and
Mainshaft (MS)
Reverse High (RH) and
Mainshaft (MS)
FL MS
FH
LS RL
RH
RL Reverse Low
FH Forward High
FIGURE 7-9
Published 04/07/2015 Control # 569-00
TRANSMISSION AND TORQUE CONVERTER
The correct operation can be confirmed as follows:
1. Chock the wheels.
2. Disable the machine neutral start protection to prevent
the engine from starting. This can be accomplished by
removing the neutral start relay located beneath the
dash. See Figure 7-10.
P0715
Neutral Start Relay Location
3. Turn the ignition switch to the ON position. Do not set the
parking brake as this dumps the transmission to a
neutral state.
4. Select the desired gear on the shifter control lever.
5. Identify the two solenoids which give the required gear
from Figure 7-9.
6. Check the magnetic attraction on the ends of the
solenoid using a feeler gauge or small screwdriver.
7. If solenoid(s) are not being energized, check that they
are receiving power.
8. If the wrong solenoids are being energized for the gear
selection check the wire harness for proper connections.
9. If the solenoids are being energized correctly and the
problem persists, the problem may be in the
transmission itself or a stuck spool in the solenoid.
NOTE: Here is a simple test if the problem seems to be
intermittent (e.g. transmission dropping to neutral).
Select a gear and place a small washer on the
ends of the energized solenoids. The washers will
be held in place by the magnetic attraction. Drive
the crane around without changing gear or
direction. If the problem reappears examine the
washers. If one or both of the washers have
dropped off, it is a good indication that there is an
electrical problem. In this case, examine the wire
harness and ECU further. If both washers are still in
place the problem lies elsewhere (possibly in the
transmission itself).
FIGURE 7-10
7
7-17