Diagnostic Guide; Diagnostic Led – Main Control (Acu); Service Diagnostic Mode; Activating Service Diagnostic Mode - Maytag MVWB835DW Service Manual

FOR SERVICE TECHNICIAN'S USE ONLY

DIAGNOSTIC GUIDE

Before servicing, check the following:
Make sure there is power at the wall outlet.

Has a household fuse blown or circuit breaker

tripped? Was a regular fuse used? Inform
customer that a time-delay fuse is required.
Are both hot and cold water faucets open

and water supply hoses unobstructed?
Make sure drain hose is not sealed into

drain pipe, and that there is an air gap for
ventilation. Ensure drain height is between
39" (991 mm) and 8' (2.4 m) above the floor.
All tests/checks should be made with a

VOM (volt-ohm-milliammeter) or DVM
(digital-voltmeter) having a sensitivity of
20,000 Ω per volt DC or greater.
Resistance checks must be made with

washer unplugged or power disconnected.
IMPORTANT: Avoid using large diameter

probes when checking harness connectors
as the probes may damage the connectors
upon insertion.
Check all harnesses and connections before

replacing components. Look for connectors
not fully seated, broken or loose wires and
terminals, or wires not pressed into connectors
far enough to engage metal barbs.
A potential cause of a control not

functioning is corrosion or contamination on
connections. Use an ohmmeter to check for
continuity across suspected connections.
When removing AC power, allow time for

the main control (ACU) to completely power
down. Verify this by examining the diagnostic
LED – it should be solidly off. At a minimum,
leave AC power removed for one minute.
DIAGNOSTIC LED – MAIN CONTROL (ACU)
A troubleshooting tool has been implemented
onto the main control board—a diagnostic LED.
LED Flashing – The Control is detecting correct
incoming line voltage and the processor is
functioning. LED OFF or ON – Control malfunction.
Perform TEST #1: Main Control (ACU), page
14, to verify main control functionality.
LED
Location
Figure 1 - Diagnostic LED
PAGE 2

SERVICE DIAGNOSTIC MODE

These tests allow factory or service personnel
to test and verify all inputs to the main control
board. You may want to do a quick and overall
checkup of the washer with these tests before
going to specific troubleshooting tests.

ACTIVATING SERVICE DIAGNOSTIC MODE

1. Be sure the washer is in standby mode
(plugged in with all indicators off).
2. Select any three (3) buttons (except
POWER) and follow the steps below, using
the same buttons (remember the buttons and
the order that the buttons were pressed):
Within 8 seconds,
• Press and Release the 1st selected button,
• Press and Release the 2nd selected button,
• Press and Release the 3rd selected button;
• Repeat this 3 button sequence 2 more times.
3. If this test mode has been entered
successfully, all indicators on the console
will be illuminated for 5 seconds with "888"
showing in the three-digit display and a tone
will sound. If there are no saved fault codes,
the seven segment display will come back
on and display "888". Upon entry to Service
Diagnostic mode, all cycles and options reset
to factory default.
NOTE: The Service Diagnostic mode will
time out after 10 minutes of user inactivity,
or shut down if AC power is removed from
the washer.
Unsuccessful Activation
If entry into diagnostic mode is unsuccessful,
refer to the following indication and action:
Indication: None of the indicators or display
turn on.
Action: Power on the washer.
 If indicators come on, try to change the
function for the three buttons used to activate
the diagnostic test mode. If any button is
unable to change the function, something
is faulty with the button, and it will not be
possible to enter the diagnostic mode using
that button. Replace the user interface.
 If no indicators come on after powering on
the washer, go to TEST #1: Main Control
(ACU), page 14.
DO NOT REMOVE OR DESTROY