WSS_SL-

WSS
STEER
AXLE
LEFT

5

WSS_SL+

1. RETARDER CONTROL VIA SAE J1939.

NOTES:

DRIVE
AXLE
LEFT
PMV

3

16 12

5

TCV_SA
3

TCV_SA_CMN

STEER
AXLE

TRACTION
CONTROL
VALVE

5

9

X3

X3

19

CAN_SEN_LO
7

CAN_SEN_SPL

CAN_SEN_HI

CAN_SEN_CMN

8 10 11

1
2

PS_SIG 3
3

YAW
RATE
SENSOR

PRESSURE
SENSOR 1
(PRIMARY
DELIVERY)

PS_SIG 1

PRESSURE
SENSOR 3
(SUSPENSION)

4

PS_CMN

PS_SIG 2
PRESSURE
SENSOR 2
(SECONDARY
DELIVERY)

PS_SPL

5

6

9

PMV_TR_CMN
12

2 1

PMV_TR_REL

PMV
TRAILER

3

PMV_TR_HLD
6

5

X4

X4

Troubleshooting: Wiring Schematic B (Alternate)
Use the wiring schematic on this
page for the following Electronic
Control Unit (ECU) part number:
K105303R000

See the previous page for a
second list of ECU part numbers.

If your ECU part number does
not appear on either list, please
call 1-800-AIR-BRAKE, option 2,
and speak with the Tech Team.

FIGURE 24 - CAB WIRING SCHEMATIC FOR ECU LISTED ABOVE
53

GLOSSARY
ABS — Antilock Brake System.
ABS Event — Impending wheel lock situation that causes the
ABS Controller to activate the modulator valve(s).
ABS Indicator Lamp — An amber lamp which indicates the
operating status of an antilock system. When the indicator lamp
is on, ABS is disabled and the vehicle reverts to normal brake
operation.

IR — Independent Regulation. A control method in which a
wheel is controlled at optimum slip, a point where retardation
and stability are maximized. The brake pressure that is best
for the wheel in question is directed individually into each brake
chamber.
J1939 — A high speed data link used for communications
between the ABS ECU engine, transmission and retarders.

Air Gap — Distance between the Sensor and tone ring.

LAS — Lateral Acceleration Sensor.

ASR — Automatic Slip Regulation. Another name for traction
control.

MIR — Modified Independent Regulation. A method of controlling
the opposite sides of a steer axle during ABS operation so that
torque steer and stopping distance are minimized.

ATC — Automatic Traction Control. An additional ABS function
in which engine torque is controlled and brakes are applied
differentially to enhance vehicle traction.
ATC/ESP Lamp — A lamp that indicates when stability functions,
including traction control, roll stability program or yaw control
are operating.
Channel — A controlled wheel site.
CAN — Controller Area Network. J1939 is an SAE version of
the CAN link.
Clear Codes — System to erase historical Diagnostic Trouble
Codes (DTCs) from the ECU, from either the Diagnostic Switch
or from a hand-held diagnostic tool (only repaired DTCs may
be cleared).
Configuration — The primary objective is to identify a “normal”
set of sensors and modulators for the Electronic Control Unit,
so that it will identify future missing sensors and modulators.
Diagnostic Connector — Diagnostic receptacle in vehicle cab
for connection of J1939 hand-held or PC based test equipment.
The tester can initiate test sequences, and can also read system
parameters.
Diagnostic Switch — A switch used to activate blinks codes.
Differential Braking — Application of brake force to a spinning
wheel so that torque can be applied to wheels which are not
slipping.

PLC — Power Line Carrier. The serial communication protocol
used to communicate with the trailer over the blue full time
power wire.
PMV — Pressure Modulator Valve. An air valve which is used
to vent or block air to the brake chambers to limit or reduce
brake torque.
QR — Quick Release. Quick release valves allow faster release
of air from the brake chamber after a brake application. To
balance the system, quick release valves have hold off springs
that produce higher crack pressures (when the valves open).
Relay Valve — Increases the application speed of the service
brake. Installed near brakes with larger air chambers (type 24
or 30). The treadle valve activates the relay valve with an air
signal. The relay valve then connects its supply port to its delivery
ports. Equal length air hose must connect the delivery ports of
the relay valve to the brake chambers.
Retarder Relay — A relay which is used to disable a retarder
when ABS is triggered.
RSP — Roll Stability Program. An all-axle ABS solution that
helps reduce vehicle speed by applying all vehicle brakes as
needed, reducing the tendency to roll over.
SAS — Steering Angle Sensor.

ECU — Electronic Control Unit.

Sensor Clamping Sleeve — A beryllium copper sleeve which
has fingers cut into it. It is pressed between an ABS sensor and
mounting hole to hold the sensor in place.

ESP — Electronic Stability Program. Full stability function that
includes RSP & YC subfunctions.

Stored Diagnostic Trouble Codes — A DTC that occurred in
the past.

Diagnostic Trouble Code — A condition that interferes with the
generation or transmission of response or control signals in the
vehicle's ABS system that could lead to the functionality of the
ABS system becoming inoperable in whole or in part.

TCS — Traction Control System, another name for ATC or ASR.

FMVSS-121 — Federal Motor Vehicle Safety Standard which
regulates air brake systems.
Hill Start (or “Hill Start Assist”) HS/HSA — This feature
interfaces between the transmission and braking system to help
the driver prevent the vehicle from rolling downhill when moving
up a steep incline from a stationary position.

54

TCV — Traction Control Valve.
Tone Ring — A ring that is usually pressed into a wheel hub that
has a series of teeth (usually 100) and provides actuation for the
speed sensor. Note maximum run out is .008.
YC — Yaw Control. Helps stabilize rotational dynamics of vehicle.
YRS — Yaw Rate Sensor.

APPENDIX A: TROUBLESHOOTING A 12-7 BLINK CODE, EQUIVALENT TO A
(SID-93 FMI-4) (SPN‑0802 FMI-04) DIAGNOSTIC TROUBLE CODE (DTC)

Bendix® EC‑80™ ESP® Electronic Control Unit (ECU)
1) Remove the X1, X2, X3 and X4 connectors from the ECU.
2) Using X1-1 as the ground connection, check for resistance
for the entire X2 connector. There should be no resistance
to ground found. Please fill out worksheet on this page.

Record Resistances
Below:
X1-1 for ground point

3) Using X1-1 as the ground connection, check for resistance
for X1-4 and X1-5. There should be no resistance to ground.

X1 Pin Resistance

4) Using X1-1 as the ground connection, check for resistance for
X3-4, X3-6, X3-7, X3-9, X3-10, X3-13, X3-3 and X3-5. There
should be no resistance to ground. (Even if the vehicle is not
configured for 6S/6M).

X1-5

5) Using X1-1 as the ground connection, check for resistance
for X4-6, X4-9 and X4-12. There should be no resistance to
ground.

X2-1

6) Troubleshoot any pin that has resistance to ground. If no
issues are found continue to step 7.

X2-4

7) Reconnect the X1 connector only and apply IGN power to the
ECU and using the DTC screen of Bendix® ACom® Diagnostic
Software, clear all DTCs. Re-check for any DTCs. If the
12-7 DTC is still present, the problem is the Traction Solenoid
Wiring or Solenoid.
8) If the 12-7 DTC does not reappear, remove power and connect
the X2 connector, reapply power, then clear all DTCs. If the
12-7 DTC is no longer present, connect the X3 connector
and clear all DTCs.

X1-4

X2 Pin Resistance
X2-2
X2-3
X2-5
X2-6
X2-7
X2-8
X2-9
X2-10
X2-11
X2-12

9) If at this point the 12-7 DTC is not present, the problem is
with the X4 connector.

X2-13

For Peterbilt® & Kenworth® Trucks Only:

X2-15

10)

Clear all DTCs. If the 12-7 DTC reappears, the issue is
on the X4 connector. Otherwise, proceed to the next step.

11)

Disconnect all modulators and the traction solenoid.
Clear all DTCs. If the DTC does not reappear, connect
one modulator and Traction Solenoid at a time, until the
DTC reappears. Otherwise, continue to the next step.

12)

Make sure all modulators and the traction solenoid are
connected. Disconnect the ABS bulkhead connector at
the engine (top-left side) and remove Pins 1, 2, 11 &12.
Reconnect the connector and apply IGN power to the
ECU. Using Bendix ACom Diagnostics, clear all DTCs.
If the 12-7 DTC returns, the problem is either the wiring
harness inside the cab or the ECU.

X2-14
X2-16
X2-17
X2-18
X3 Pin Resistance
X3-4
X3-5
X3-6
X3-7
X3-8

4

X3-9
X3-10
X3-13
X4 Pin Resistance
X4-6
X4-9
X4-12

55

®

APPENDIX B: J1939 SPN AND FMI CODES AND THEIR BENDIX BLINK CODE EQUIVALENTS
SPN
(J1939)

56

FMI
(J1939)

Bendix® Blink Code
Equivalent(s)
Diagnostic Trouble Code (DTC) Description
(1st
(2nd
Digit)
Digit)

Lamp Status
ABS

ATC/
ESP

-

-

-

1

1

No DTCs

168
168

3
4

6
6

2
1

Power Supply DTCs
Battery Voltage Too High
Battery Voltage Too Low
Miscellaneous DTCs

ON
ON

ON
ON

564

3

25

3

Differential Lock Solenoid Shorted To Voltage

ON

ON

564
564
564

4
5
13

25
25
25

2
1
7

ON
ON
ON

-

575

14

12

17

-

ON

576

14

12

3

ON

-

614

3

12

32

-

ON

614
614
614
614
615
615

3
4
5
13
14
14

25
25
25
25
12
12

6
5
4
8
19
20

-

ON
ON
ON
ON
-

614

3

12

32

-

ON

614
614
614
614
615
615

3
4
5
13
14
14

25
25
25
25
12
12

6
5
4
8
19
20

-

ON
ON
ON
ON
-

629
629
629
629