MBE 900 4000 Troubleshooting

Section 2.3 Vehicle Control Unit— On-Highway

Section 2.3
Vehicle Control Unit— On-Highway

The DDEC-VCU is the interface between the PLD-MR and the truck for engine control and manages other vehicle functions. ‪

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Figure 1. The Vehicle Control Unit

The DDEC-VCU also communicates over the J1587 and J1939 Data Links to the vehicle (see Figure "NAFTA Architecture" ).‪

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Figure 2. NAFTA Architecture

Within the DDEC-VCU, sets of data for specific applications are stored. These include idle speed, maximum running speed, and speed limitation.‪

The DDEC-VCU receives data from the operator (accelerator pedal position, switches, various sensors) and other electronic control units (for example, the anti-lock brake system, transmission controllers).‪

From this data, instructions are computed for controlling the engine and transmitted to the PLD-MR via the proprietary data link.‪

Section 2.3.1
Vehicle Interface Harness Design

The OEM supplied Vehicle Interface harness (VIH) connects the DDEC-VCU to the PLD-MR and other vehicle systems (see Figure "Typical On-Highway Vehicle Interface Harness with a DDEC-VCU" ).‪

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Figure 3. Typical On-Highway Vehicle Interface Harness with a DDEC-VCU

Section 2.3.1.1
Digital Inputs

The DDEC-VCU has 18 digital inputs located on the VIH. These inputs are in low state by providing a connection to battery ground and placed in high state by providing an open circuit.‪

Digital Input Requirements:

High State:‪

Battery (+) >Ein > 7.0 V‪

Low State:‪

Vin < 3.0 V‪

Isink:‪

Capable of sinking 5–20 mA‪

The digital inputs are listed in Table "Digital Inputs" .‪

Connector Pin‪

Description‪

Vmax

Vmin

Pull-up Resistor‪

Input Requirement‪

DDEC-VCU 15/01‪

Transmission Neutral‪

VBat

0 V‪

2.35 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 15/02‪

Dual Road Speed Axle‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/02‪

Clutch Switch‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/04‪

Cruise Control Set/Coast‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/05‪

Cruise Control Resume/Accel‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/06‪

Cruise Control On/Off Switch‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/07‪

Throttle Select‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/08‪

Engine Brake Low‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/09‪

Engine Brake High‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/10‪

Remote PTO Switch‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/11‪

Limiter 0‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/12‪

Limiter 1‪

VBat

0 V‪

2.35 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/13‪

Shutdown Override Switch‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/14‪

Air Conditioner‪

(Limiter 2)‪

VBat

0 V‪

2.35 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/15‪

Fan Override‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 18/16‪

Throttle Inhibit‪

VBat

0 V‪

5 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 21/15‪

Service Brake Switch‪

VBat

0 V‪

2.35 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

DDEC-VCU 21/16‪

Park Brake Switch‪

VBat

0 V‪

2.35 kΩ‪

V on<3.0 V‪

V off>7.0 V‪

Table 2. Digital Inputs
Section 2.3.1.2
Analog Inputs

The analog inputs are listed in Table "Analog Inputs" .‪

Pin‪

Description‪

VBat

Vmin

Pull-up or Pull-down Resistor‪

15/07‪

Engine Coolant Level Sensor‪

5 V‪

0 V‪

440 Ω to 5 V Pull-up‪

15/08‪

Air Filter Restriction Sensor‪

5 V‪

0 V‪

200 kΩ to 5 V Pull-up‪

18/18‪

Remote Throttle Signal‪

5 V‪

0 V‪

200 kΩ to 5 V Pull-up‪

21/11‪

Accelerator Pedal Signal‪

5 V‪

0 V‪

Williams Pedal Terminal A, 47 kΩ to Ground Pull-down‪

Table 3. Analog Inputs
Section 2.3.1.3
Digital Outputs

The digital outputs are listed in Table "Digital Outputs" .‪

Pin‪

Description‪

IMax

VBat

PMax Lamp‪

Output Type‪

DDEC-VCU 15/05‪

Power Supply Accelerator Pedal PWM‪

2 A‪

VBat

—‪

High-side Driver‪

Gear Out 1‪

DDEC-VCU 15/06‪

Engine Brake 2, Exhaust Flap‪

2 A‪

VBat

—‪

High-side Relay Driver‪

DDEC-VCU 15/09‪

Relay 2‪

2 A‪

VBat

—‪

Low-side Relay Driver‪

DDEC-VCU 15/10‪

Engine Brake 1, Constant Throttle‪

1.8 A‪

VBat

—‪

High-side Relay Driver‪

DDEC-VCU 15/11‪

Relay 3‪

250 mA‪

VBat

—‪

Low-side Relay Driver, Short Protected‪

DDEC-VCU 15/12‪

Relay 1‪

1.3 A‪

VBat

—‪

Low-side Relay Driver, Short Protected‪

DDEC-VCU 18/01‪

Relay 4‪

1.3 A‪

VBat

—‪

Low-side Relay Driver, Short Protected‪

DDEC-VCU 18/03‪

Idle Validation Switch Ground‪

250 mA‪

0 V‪

—‪

Input for William's Pedal Terminal F‪

DDEC-VCU 21/04‪

Oil Level Lamp‪

250 mA‪

VBat

2 W at 12 V‪

Low-side Relay Driver, Short Protected‪

DDEC-VCU 21/05‪

Red Stop Lamp‪

250 mA‪

VBat

2 W at 12 V‪

Low-side Relay Driver, Short Protected‪

DDEC-VCU 21/06‪

Amber Warning Lamp‪

150 mA‪

VBat

2 W at 12 V‪

Low-side Relay Driver, Short Protected‪

DDEC-VCU 21/07‪

Wait to Start Lamp‪

250 mA‪

VBat

2 W at 12 V‪

Low-side Relay Driver, Short Protected‪

DDEC-VCU 21/08‪

Air Filter Lamp‪

250 mA‪

VBat

2 W at 12 V‪

Low-side Relay Driver, Short Protected‪

Table 4. Digital Outputs
Section 2.3.1.4
Data Links

The Data Links that provide the communication interface are listed in Table "Communication Interface Data Links" .‪

Pin‪

Description‪

Potential‪

UBat

Umin

Further Data‪

15/15‪

Engine-CAN (Low)‪

—‪

2/3 VBat

1/3 Vmin

ISO/DIS 11992, One Wire Capability‪

15/14‪

CAN-HF-Ground‪

GND‪

—‪

—‪

100 nF to Ground‪

15/13‪

Engine-CAN (High)‪

—‪

2/3 VBat

1/3 Vmin

ISO/DIS 11992, One Wire Capability‪

21/17‪

SAE 1708, A‪

—‪

—‪

—‪

Only Partly Implemented‪

21/18‪

SAE 1708, A‪

—‪

—‪

—‪

Only Partly Implemented‪

21/19‪

SAE J1939 CAN (High)‪

5 V‪

—‪

—‪

—‪

21/20‪

CAN-HF-Ground‪

GND‪

—‪

—‪

100 nF to ground‪

21/21‪

SAE J1939 CAN (Low)‪

5 V‪

—‪

—‪

—‪

Table 5. Communication Interface Data Links
Section 2.3.1.5
Ignition

The ignition source is 12 volts. The DDEC-VCU and PLD-MR ignition must be an independent input sourced directly from the battery post via a weatherproof blade type fuse, circuit breaker, or equivalent. Ignition sinks a maximum of 25 mA. The ignition fuse rating must be sized for the loads utilized in the application; however, a rating between 5 and 10 amps is usually sufficient. Fuse holders for blade type fuses may be purchased from the DDC Parts Distribution Center. The fuse holder accepts a wire diameter with an OD of 2.89 - 3.65 mm. Part numbers are listed in Table "Fuse Holder Part Numbers" .‪

Part‪

Part Number‪

Fuse Holder‪

12033769‪

Cover‪

12033731‪

Terminals‪

12066614‪

Table 6. Fuse Holder Part Numbers

Ignition voltage must be provided in the crank and run modes.‪

Section 2.3.2
Vehicle Interface Harness Wiring

The wiring for the VIH 15–pin connector to the DDEC-VCU is listed in Table "DDEC-VCU 15–Pin VIH Connector Pin Assignments" . The side of the connector shown is looking into the pins.‪

Pin‪

Signal Type‪

Function‪

Connector‪

15/01‪

Digital Input – Switch to Ground, Normally Open, Disables Engine Start if Closed‪

Transmission Neutral Switch‪

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Front‪

Looking into the Pins on the Harness‪

15/02‪

Digital Input – Switch to Ground, Normally Open, Sets Speed Ratio if Closed‪

Dual Speed Axle‪

15/03‪

Data Link‪

Vehicle Speed Signal Input for Tachometer‪

15/04‪

—‪

Reserved‪

15/05‪

Configurable High Side Digital Output‪

Power Supply for PWM Pedal‪

Gear Out 1, Output for Modulation Valve (e.g. Allison Automatic Transmission)‪

15/06‪

Configurable High Side Digital Output‪

Engine Brake 2, Exhaust Flap‪

15/07‪

Analog Input‪

Engine Coolant Level Sensor‪

15/08‪

Analog Input‪

Air Filter Sensor‪

15/09‪

Configurable High Side Digital Output‪

Relay 2‪

The configurable parameters are listed in Table "Configurable Parameters on the DDEC-VCU 15- and 18-Pin Connectors" .‪

15/10‪

Configurable High Side Digital Output‪

Engine Brake 1, Decompression Valve‪

15/11‪

Configurable Low Side Digital Output‪

Relay 3‪

The configurable parameters are listed in Table "Configurable Parameters on the DDEC-VCU 15- and 18-Pin Connectors" .‪

15/12‪

Configurable Low Side Digital Output‪

Relay 1‪

The configurable parameters are listed in Table "Configurable Parameters on the DDEC-VCU 15- and 18-Pin Connectors" .‪

15/13‪

Data Link‪

MBE Proprietary CAN (+) (PLD-MR)‪

15/14‪

Data Link‪

MBE Proprietary CAN Shield (PLD-MR)‪

15/15‪

Data Link‪

MBE Proprietary CAN (-) (PLD-MR)‪

Table 7. DDEC-VCU 15–Pin VIH Connector Pin Assignments

Pin‪

Function‪

Parameters‪

15/12‪

Relay 1‪

0 = Disabled‪

1 = Starter Protection‪

2 = Acc. Pedal Kick Down position‪

3 = Transmission Output 1‪

15/09‪

Relay 2‪

0 = Disabled‪

1 = Grid Heater‪

2 = Acc. Pedal Idle Position‪

15/11‪

Relay 3‪

0 = Acc. Pedal Idle Position‪

1 = Actual Torque‪

2 = Vehicle Speed‪

3 = Engine Speed‪

4 = Coolant Temperature‪

5 = Acc. Pedal Torque‪

6 = Booster Temperature‪

7 = Oil Pressure Warning Lamp‪

8 = Coolant Temp Warning Lamp‪

18/01‪

Relay 4‪

0 = Kickdown Position‪

1 = Actual Torque‪

2 = Vehicle Speed‪

3 = Engine Speed‪

4 = Coolant Temp‪

5 = Pedal Torque‪

6 = Booster Air Temp‪

7 = Oil Pressure Warning Lamp‪

8 = Coolant Temp Warning Lamp‪

18/08‪

Engine Brake Low, Engine Brake Switches Low and High‪

0 = Not Active‪

1 = Active‪

18/09‪

Engine Brake High‪

High‪

0‪

0‪

1‪

1‪

/Low‪

0 = Engine Brakes Disabled‪

1 = Engine Brake Step 1: Decompression Valve Enabled‪

0 = Engine Brake Step 2: Decompression Valve and Exhaust Flap Enabled‪

1 = Not Implemented‪

Table 8. Configurable Parameters on the DDEC-VCU 15- and 18-Pin Connectors

The wiring for the VIH 18–pin connector to the DDEC-VCU is listed in Table "DDEC-VCU 18–Pin VIH Connector Pin Assignments" . The side of the connector shown is looking into the pins.‪

Pin‪

Signal Type‪

Function‪

Connector‪

18/01‪

Configurable Low Side Digital Output‪

Relay 4‪

The configurable parameters are listed in Table "Configurable Parameters on the DDEC-VCU 15- and 18-Pin Connectors" .‪

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Front‪

Looking into the Pins on the Harness‪

18/02‪

Digital Input – Normally Closed (open if clutch is pressed)‪

Clutch Switch 1‪

18/03‪

Digital Input‪

Idle Validation Switches‪

18/04‪

Digital Input – Normally Open‪

Cruise Control, Set/Coast‪

18/05‪

Digital Input – Normally Open‪

Cruise Control, Res/Accel‪

18/06‪

Digital Input – Normally Open‪

Cruise Control, On/Off‪

18/07‪

Digital Input – Normally Open‪

Remote Accelerator Select Switch‪

18/08‪

Digital Input – Normally Open‪

Engine Brake Low, Engine Brake Switches Low and High‪

The configurable parameters are listed in Table "Configurable Parameters on the DDEC-VCU 15- and 18-Pin Connectors" .‪

18/09‪

Digital Input – Normally Open‪

Engine Brake High‪

The configurable parameters are listed in Table "Configurable Parameters on the DDEC-VCU 15- and 18-Pin Connectors" .‪

18/10‪

Digital Input – Normally Open‪

Remote PTO Switch‪

18/11‪

Digital Input – Normally Open‪

Limiter 0‪

18/12‪

Digital Input – Normally Open‪

Limiter 1‪

18/13‪

Digital Input – Normally Open‪

Engine Shutdown Override‪

18/14‪

Digital Input – Normally Open‪

Limiter 2 (Air Condition Status – Fast Idle)‪

18/15‪

Digital Input – Normally Open‪

Fan Override‪

18/16‪

Digital Input – Normally Open‪

Throttle Inhibit‪

18/17‪

Sensor Supply‪

Remote PTO Power Supply and Air Cleaner Sensor‪

18/18‪

Analog Input‪

Remote Throttle Signal‪

Table 9. DDEC-VCU 18–Pin VIH Connector Pin Assignments

The wiring for the VIH 21–pin connector for the DDEC-VCU is listed in Table "DDEC-VCU 21–Pin VIH Connector Pin Assignments" . The power and communication links are wired through this connector. The side of the connector shown is looking into the pins.‪

Pin‪

Signal Type‪

Function‪

Connector‪

21/01‪

—‪

Battery Voltage‪

21/02‪

Digital Input‪

Ignition (+12 V)‪

21/03‪

—‪

Battery Ground‪

21/04‪

Digital Output – Low Side‪

Oil Level Lamp*‪

21/05‪

Digital Output – Low Side‪

Red Stop Lamp*‪

21/06‪

Digital Output – Low Side‪

Amber Warning Lamp*‪

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Front‪

Looking into the Pins on the Harness‪

21/07‪

Digital Output – Low Side‪

Wait to Start Lamp‪

21/08‪

Digital Output – Low Side‪

Air Filter Warning Lamp‪

21/09‪

Sensor Supply‪

Accelerator Pedal Power Supply (+5 V supply)‪

21/10‪

Digital Input – Normally Open‪

Plug (not used, must be plugged)‪

21/11‪

Analog Input‪

Accelerator Pedal Signal‪

21/12‪

Pulse Input‪

PWM Throttle Signal, Path 1‪

Idle Validation 2 (Throttle Active)‪

21/13‪

Pulse Input‪

PWM Throttle Signal, Path 2‪

Idle Validation 1 (Idle Active)‪

21/14‪

—‪

PWM Accelerator Pedal Ground‪

Analog Pedal Ground‪

21/15‪

Digital Input – Normally Closed‪

Service Brake Switch‪

21/16‪

Digital Input – Normally Open‪

Park Brake Switch‪

21/17‪

Data Link‪

SAE J1708 (+)‪

21/18‪

Data Link‪

SAE J1708 (-)‪

21/19‪

Data Link‪

SAE J1939 (+)‪

21/20‪

Data Link‪

J1939 Shield‪

21/21‪

Data Link‪

SAE J1939 (-)‪

Table 10. DDEC-VCU 21–Pin VIH Connector Pin Assignments

* If output is active while engine is running, shut down the engine immediately and initiate an error diagnosis.
Section 2.3.2.1
VIH to PLD-MR Connector Wiring

The wiring for the VIH 16–pin to the PLD-MR is listed in Table "16–Pin Connector to the PLD-MR" . The side of the connector shown is looking into the pins.‪

Pin‪

Signal Type‪

Function‪

Connector‪

1‪

Data Link‪

CAN Interface (High Line)‪

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Front‪

Looking into the Pins on the Harness‪

2‪

Data Link‪

CAN Interface (Low Line)‪

3‪

Data Link‪

CAN HF Ground‪

4‪

Data Link‪

CAN HF Ground‪

5‪

Power Supply‪

Battery Voltage (+)‪

6‪

Power Supply‪

Battery Voltage (+)‪

7‪

NC‪

NC‪

8‪

Digital Output‪

Starter Control Signal‪

9‪

Ground‪

Battery Ground (-)‪

10‪

Digital Output‪

Proportional Valve 1–4 High Side Supply‪

11‪

Ground‪

Battery Ground (-)‪

12‪

Digital Output‪

Starter High Side Control‪

13‪

Digital Data Link‪

Diagnostic Link K-line (ISO)‪

14‪

Digital Output‪

Proportional Valve 3 Low Side Control‪

15‪

Ignition Input‪

Ignition‪

16‪

Digital Output‪

Proportional Valve 4 Low Side Control‪

Table 11. 16–Pin Connector to the PLD-MR
Section 2.3.2.2
VIH to Engine Harness Connector Wiring

The wiring for the 8-pin connector to the Engine Harness required for engine brakes and fan control for the MBE 4000 is listed in Table "Engine Harness Connector for Engines with Two Solenoid Air Valves for Engine Brakes — MBE 4000 Only" .‪

Description‪

Engine Harness 8–pin Connector‪

PLD-MR 55–pin Connector‪

Fan Control —Control 31, Switch to Bat- (PV3)‪

A‪

41‪

Fan Control No. 2, Switch to Bat- (PV4)‪

B‪

43‪

Compression Brake Control, Switch to Bat- (PV2)‪

C‪

50‪

Fan and Wastegate/E-Flap Voltage Supply (PV1,3,4)‪

D‪

12‪

Exhaust Flap/Wastegate Control, Switch to Bat- (PV1)‪

E‪

51‪

Compression Brake Voltage Supply (PV2)‪

F‪

52‪

Turbo Brake Control, Switch to Bat-(PV6)‪

G‪

40‪

Turbo Brake Voltage Supply (PV6)‪

H‪

42‪

Table 12. Engine Harness Connector for Engines with Two Solenoid Air Valves for Engine Brakes — MBE 4000 Only

See Figure "MBE 4000 Non-EGR Engine Brake" for an engine brake schematic.‪

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Figure 4. MBE 4000 Non-EGR Engine Brake

The wiring for the 8-pin connector to the Engine Harness required for Engine Brakes and Fan Control for the Non-EGR MBE 900 is listed in Table "Engine Harness Connector for MBE 900 Non-EGR Engine" . See Figure "MBE 900 Non-EGR VIH to Engine Harness Wiring" for a schematic.‪

Description‪

Engine Harness‪

Connector/Pin‪

PLD-MR 55 Pin Connector‪

Fan Control, Switch to Bat- (PV3, PV4)‪

Y70/Pin 1‪

41‪

Fan Control Power‪

Y70/ Pin 2‪

12‪

Compression Brake Control, Switch to Bat- (PV2)‪

Y49/ Pin 1‪

50‪

Compression Brake Power‪

Y49/Pin 2‪

52‪

Exhaust Flap Control, Switch to Bat- (PV1)‪

Y91/Pin 1‪

51‪

Exhaust Flap Power‪

Y91/Pin 2‪

12‪

Table 13. Engine Harness Connector for MBE 900 Non-EGR Engine
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Figure 5. MBE 900 Non-EGR VIH to Engine Harness Wiring

The wiring for the 8-pin connector to the Engine Harness required for engine brakes and fan control for the MBE 900 EGR engine is listed in Table "Engine Harness Connector for MBE 900 EGR Engine" . See Figure "Engine Harness Connector for MBE 900 EGR Engine" for a schematic.‪

Description‪

Engine Harness‪

Connector/Pin‪

PLD-MR 55 Pin Connector‪

Fan Control, Switch to Bat- (PV3, PV4)‪

Y70/Pin 1‪

41‪

Fan Control Power‪

Y70/ Pin 2‪

12‪

Compression Brake Ground‪

Y49/ pin 1‪

11‪

Compression Brake Control, Switch to Bat+ (PV5)‪

Y49/Pin 2‪

27‪

Exhaust Flap Control, Switch to Bat- (PV1)‪

Y91/Pin 1‪

51‪

Exhaust Flap Power‪

Y91/Pin 2‪

12‪

Table 14. Engine Harness Connector for MBE 900 EGR Engine
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Figure 6. Engine Harness Connector for MBE 900 EGR Engine

Section 2.3.2.3
VIH Power Wiring

The OEM-supplied VIH power wiring (see Figure "Power Wiring " ) supplies 12 volts to the DDEC-VCU and PLD-MR. The system must be sourced directly from the battery. The terminals are designed to accept 14 AWG standard wall wire.‪

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Figure 7. Power Wiring

Power must be sourced directly from the battery. An electrically solid connection to the battery or bus bar is required so the battery can filter electrical noise from the power lines. Power for other vehicle systems must not be sourced from the VIH power wires. Do not use chassis ground.‪

Note: The ground wire must be electrically separate from chassis ground.

Power and ground bus bars may be used. The bus bar must be connected to the battery posts with 0 AWG or larger wire depending upon the total vehicle current requirement. The connecting wires must be as short as possible to minimize circuit resistance. Do not connect the ground wire to the chassis ground.‪

Section 2.3.2.4
Communications – SAE J1939 Data Link

SAE J1939 Data Link (+), SAE J1939 Data Link (-), and SAE J1939 Data Link Shield are used as the J1939 communication link. J1939 cable is required for the J1939 data link. Termination resistors are required per the SAE specification. Refer to SAE J1939–11 for specific requirements.‪

The DDEC-VCU connector pin assignments for SAE J1939 are listed in Table "J1939 DDEC-VCU to VIH Connector Pin Assignments" .‪

Pin‪

Signal Type‪

Function‪

21/19‪

Data Link‪

SAE J1939 (+)‪

21/20‪

Data Link‪

J1939 Shield‪

21/21‪

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