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the entire antilock system including wiring continuity. A dash
lamp, controlled by the EC-14

 controller, advises the driver

of the condition of the entire antilock system. The condition
of specific antilock components is provided to the mechanic
by a series of labeled, light emitting diodes (LED’s) displayed
through a “window” in the EC-14

 controller housing. No

special tools or equipment are needed to read or interpret
the EC-14

 controller diagnostics window. It should be noted

that the diagnostics display is separate from the antilock
condition lamp on the dash. With this separation, the driver
is aware of any problems that occur, but is not concerned
with in-depth diagnostic information.

A special feature of the EC-14

 controller diagnostic system

is its failure latching. Intermittent problems, particularly in
the wheel speed sensing area can be difficult to diagnose.
When the controller senses an erroneous condition, whether
in the controller electronics, the modulator or speed sensing
areas, it stores the condition in non-volatile memory, disables
the antilock function if necessary, illuminates the dash
mounted antilock condition lamp and the appropriate
diagnostic LEDs on the EC-14

 controller. The malfunction

condition is truly stored and is not cleared by loss of power
to the EC-14

 controller. The LEDs will re-light when power

is restored and remain illuminated until the problem is
corrected. After the actual problem is corrected, maintenance
personnel can clear or reset the EC-14

 controller

diagnostics by passing a small magnet over the RESET
point in the diagnostics window.

DIAGNOSTIC LEDS

There are nine LEDs plus a magnetically actuated reset
switch in the EC-14

 controller diagnostic window. The first

five LEDs locate a problem to a specific area of the trailer
while the last four indicate the problem component or its
wiring. The LEDs are computer controlled and are either ON
or OFF depending upon their monitor function. (Note: Right
and left, front and rear are determined from the driver's seat.
Left front is therefore the corner closest to the driver.)

LED

o FRONT Red LED

LED

o MID

Red LED  (SEE NOTE)

LED

o REAR

Red LED

LED

o RIGHT Red LED

LED

o LEFT

Red LED

LED

o MOD

Red LED

LED

o SENS Red LED

LED

o ECU

Red LED

LED

o VOLT

Green LED

¦ ¦ ¦

RESET

No LED

Note:

The MID LED shown in the chart above is not used
in the diagnostic process for the EC-14

 controller

however, it will light when a magnet is placed on the
RESET switch in the diagnostic window.

"FRONT" LED

This Red LED illuminates and latches on in order to indicate
the location of a problem component or its wiring. It will light
in conjunction with either the RIGHT or LEFT LED and the
SENS LED when indicating a speed sensor problem. The
FRONT LED will also light in conjunction with the MOD LED
to indicate that the front modulator (M-21

 or M-22

) or its

wiring has malfunctioned.

"MID" LED

This red LED is not used in troubleshooting the EC-14

controller and should light only when a magnet is held on
the RESET switch.

"REAR" LED

This red LED illuminates and latches on in order to indicate
the location of a problem component or its wiring. It will light
in conjunction with either the RIGHT or LEFT LED and the
SENS LED when indicating a speed sensor problem. The
REAR LED will also light in conjunction with the MOD LED
to indicate that the rear modulator (M-12

) or its wiring has

malfunctioned.

FIGURE 8 - EC-14

 CONTROLLER DIAGNOSTIC WINDOW

Содержание EC-14 ANTILOCK CONTROLLER

Страница 1: ...system are contained in a die cast aluminum housing and are environmentally protected by silicone encapsulation The metal housing coupled with the design of the digital electronics is intended to pro...

Страница 2: ...2 FIGURE 2 MC 14 ANTILOCK BRAKE SYSTEM...

Страница 3: ...l speed information from various wheel speed sensor models at the rate of 100 pulses per wheel revolution The EC 14 controller is able to simultaneously receive and individually interpret speed signal...

Страница 4: ...ONNECTOR DEUTSCH 2 PIN CONNECTOR 90 WS 20 WHEEL SPEED SENSOR STRAIGHT WS 20 WHEEL SPEED SENSOR BRAKE DRUM SPEED SENSOR MOUNTING BLOCK 100 TOOTH SPEED SENSOR EXCITER RING WS 20 WHEEL SPEED SENSOR 90 DE...

Страница 5: ...eans of advising the driver of the condition of the antilock system A connection to the Engine or Transmission Retarder is provided on the EC 14 controller which allows the EC 14 controller to tempora...

Страница 6: ...NON ANTILOCK BRAKE APPLICATION During normal braking the brake valve simultaneously delivers air to the control port of the M 12 modulator on the rear axle s as well as to and through the M 21 or M 22...

Страница 7: ...rformed during this period Because no two vehicles operate under identical conditions maintenance and maintenance intervals will vary Experience is a valuable guide in determining the best maintenance...

Страница 8: ...8 FIGURE 6 MC 14 ANTILOCK WIRING SCHEMATIC...

Страница 9: ...tion of the MC 14 modulator controller assembly on the vehicle Loosen remove and save the nuts on the mounting hardware that attaches the MC 14 modulator controller bracket to the vehicle Remove the M...

Страница 10: ...DS There are nine LEDs plus a magnetically actuated reset switch in the EC 14 controller diagnostic window The first five LEDs locate a problem to a specific area of the trailer while the last four in...

Страница 11: ...during vehicle operation to indicate that vehicle power is reaching the controller If vehicle power is out of range for proper operation below 10 vdc or above 17 vdc this LED will flash until power is...

Страница 12: ...odulators Go to Section I Dash Lamp Testing YES YES NO Dash lamp remains on NO Go to Section III Inspection for illuminated LEDs YES NO The system is functioning normally Make notes of the parts repla...

Страница 13: ...on on measure voltage between lamp relay Pin 3F and ground Pins 1A 2A Voltage should be same as battery voltage Replace the EC 14 controller Go to Section II Inspection for Illuminated LEDs Check wiri...

Страница 14: ...nspection for Illuminated LEDs NO Record the condition of all red LEDs Go to Section IX Testing for False Failure Indication Caused by Dash Lamp Relay NO Go to Section V Testing for Power to the EC 14...

Страница 15: ...lluminated Go to Section IV Inspection for Illuminated LEDs Record the condition of all red LEDs Go to Section X Testing For False Failure Indication Caused by Wheel Speed Components NO Go to Section...

Страница 16: ...NO Is the red FRONT or REAR LED illuminated See Note 1 below Is the red FRONT or REAR LED illuminated See Note 1 below NO YES REAR LED FRONT LED Go to Section VII Testing the Rear Modulator ON ON ON...

Страница 17: ...een power and ground pins on wire harness connector 1A to 1K 1A to 2K 2A to 1 K 2A to 2 K Reconnect connector to EC 14 controller Check the vehicle wiring for continuity Refer to the vehicle service m...

Страница 18: ...o Power 2F to 1K 2K No Continuity Exhaust to Ground 2F to 1A 2A No Continuity NO Go to Section VI B and continue testing Are resistance values correct 1A 2A GROUND 2F EXHAUST 2G HOLD 1K 2K POWER 1G SO...

Страница 19: ...Test each pin to vehicle ground and note no continuity Are resistance values correct Replace the front M 21 modulator NO Reconnect connector to modulator Turn ignition on and pass magnet over RESET o...

Страница 20: ...NET HERE YES STARTHERE Turn the ignition off Separate the EC 14 controller from the M 12 modulator Disconnect the four pin connector between the two components and test resistance on the modulator con...

Страница 21: ...If sensor gap must be adjusted check for loose or worn wheel bearings before re gapping sensor Refer to vehicle maintenance manual for worn bearings C If sensor gap is correct check wheel bearing for...

Страница 22: ...esistance between two pins on sensor Is resistance between 1500 2500 Ohms for the Bendix WS 20 speed sensor NO Replace the sensor YES NO Reconnect connector at speed sensor and EC 14 controller Pass m...

Страница 23: ...mation Repair or replace as necessary and repeat the Initial Start up Procedure Repeat the Initial Start up Procedure If testing has returned to this step twice replace the EC 14 controller and retest...

Страница 24: ...onds or more Bring vehicle to a stop and turn off ignition Turn the ignition off Refer to Section VII Part A Testing the wheel sensor and perform tests and inspections B through F in the large box Rep...

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