Bendix Commercial Vehicle Systems WINGMAN ACB ACTIVE CRUISE W/BRAKING - Manual (Page 24)

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4.6 SERIAL DATA (J1939)
COMMUNICATIONS LINK
Check for a loss of communications between the Bendix ®
Wingman ® ACB system radar sensor, the ABS controller,
the engine ECU, and other devices connected to the
J1939 link. Check for damaged or reversed J1939 wiring.
Check for corroded or damaged connectors and loose
connections. Using procedures described by the vehicle
manufacturer, verify the presence of the engine ECU and
the ABS controller on the J1939 link.
Verify the engine ECU con fi guration. Check for other
devices inhibiting J1939 communications.
4.7 ENGINE COMMUNICATIONS
(J1939) TEST PROCEDURE
The Wingman ACB system requires several J1939
messages from the engine ECU to control the engine
and retarder torque for distance control and braking. The
Wingman ACB system will set a diagnostic trouble code if
one of these messages is not present.
Use the engine manufacturer’s diagnostic test procedures
to verify that there are no errors present in the engine that
may prevent the Wingman ACB system from controlling
the engine or retarder torque.
4.7.1 J1939 TROUBLESHOOTING
PROCEDURE
1. Take all measurements at the harness connector unless
otherwise indicated.
CAUTION: DO NOT INSERT PROBES INTO THE BACK
SIDE OF THE CONNECTOR AS THIS WILL DAMAGE THE
SEAL AROUND THE WIRE
.
CAUTION: DO NOT INSERT ANY PROBE INTO THE
PIN ON THE MATING CONNECTOR OF THE RADAR
SENSOR THAT IS GREATER THAN 0.62 MM DIAMETER
OR SQUARE. THIS WILL DAMAGE THE CONNECTOR PIN
AND REQUIRE REPLACEMENT OF THE HARNESS
.
2. Check for damaged or reversed J1939 wiring.
If the J1939 HIGH or J1939 LOW wiring circuits are
damaged, such as shorting together, the entire J1939
link will be lost. The problem may be intermittent,
enabling the J1939 link to operate normally sometimes.
In that event, multiple diagnostic trouble codes will be
logged in multiple engine and vehicle controllers.
If the J1939 HIGH and J1939 LOW wiring circuits are
reversed, communication over the entire J1939 link will
not be lost. Only those devices that are outside of the
problem point from other devices will not receive, or be
able to transmit, data messages.
3. Check for corroded or damaged wiring connector
problems such as opens or shorts to voltage or ground.
If the connector terminals are corroded, this may be
an indication of water intrusion into the wiring system
and possibly into the radar sensor. Replacement of
the entire harness is recommended. If the terminals
of the radar sensor are corroded, replacement of the
radar sensor is recommended.
4. Check for other J1939 devices which may be inhibiting
J1939 communication. The service technician should
consult the vehicle manufacturer’s procedures for
other J1939 troubleshooting procedures. The device’s
power should be removed and measurements made at
the ECU pins for shorts to ground and power pins and
resistance between the J1939 HIGH or J1939 LOW
input circuits.
5. Unplug the radar sensor. With the ignition switch off,
measure the resistance (ohms) using a multimeter
between harness pins 2 and 3. The reading should be
approximately 60 ohms. If it is not, the vehicle wiring
should be investigated using procedures described by
the manufacturer.
6. Unplug the radar sensor. With the ignition switch off,
using a multimeter, measure the resistance in ohms,
between harness pins 2 and ground. The measurement
should indicate an open circuit or very high resistance.
If this is not the case, the vehicle wiring should be
investigated using procedures described by the
manufacturer.
7. Unplug the radar sensor. With the ignition switch off,
using a multimeter, measure the resistance in ohms,
between harness pins 3 and ground. The measurement
should indicate an open circuit or very high resistance.
If this is not the case, the vehicle wiring should be
investigated using procedures described by the
manufacturer.
4.8 TROUBLESHOOTING
WIRING HARNESSES
All wire harness connectors must be properly seated to
maintain environmental seals. Push the mating connector
until it seals with a click. When replacing an ACB radar
sensor, check that the wire harness connector is free of
corrosion before plugging into a new radar sensor. Check
for corroded or damaged wiring connector problems such
as opens or shorts to voltage or ground.
If the connector terminals are corroded, this may be an
indication of water intrusion into the wiring system and
possibly into the radar sensor. Replacement of the entire
harness is recommended. If the terminals of the radar
sensor are corroded, replacement of radar sensor is
recommended.