J1939 Based Switch Messages

15.0 J1939 Based Switch Messages

The Powertrain Data Link parameter must be programmed to J1939 before the ECM will respond to messages received from the J1939 data link.Individual switch input parameters must be programmed to receive messages from either the Cab Controller (source address 49, $31), the Body Controller (source address 33, $21) or the Instrument Cluster (source address 23, $17).All programmed switch inputs require that the status of the switch bebroadcast as On or Off when the key switch is On.Not broadcasting a switch status message will result in a diagnostic code to be active and the Check Engine lamp will be enabled.

15.1 Cruise Switch Inputs 15.1.1 Cruise Control On/Off Switch Cruise Switch (PGN 65265 ($FEF1) Byte 4,bits 4,3 is set to 01)

The Cruise switch will allow enabling cruise control, if turned on and will deactivate (kickout) cruise control ifswitched off.The switch must be in the On position to activate cruise control.

15.1.2 Cruise Control Set Switch Set Switch (PGN 65265 ($FEF1) Byte 5,bits 2,1 set to 01)

As long as the Cruise switch is Off the Set switch has no functionality for the cruise feature.If the Cruise On/Off switch is on and all other conditions are met (Veh spd, Clutch, Brake, Neutral, Cruise Pause) an On/Off transition ofthe Set switch will activate cruise and set the cruise target speed to the actual vehicle speed.As long as Cruise stays active, any other On/Off, Off/On or hold transition of the Set switch will be ignored.The Set switch is only used to activate Cruise, set the current veh spd = cruise target speed and enable the Accel and Decel switch.

15.1.3 Cruise Control Resume Switch Resume switch (PGN 65265 ($FEF1) Byte 5,bits 6,5 set to 01)

As long as the Cruise switch is Off the Resume switch has no functionality for the cruise feature.If the Cruise On/Off switch is on and all other conditions are met (Veh spd, Clutch, Brake, Neutral, Cruise Pause) an On/Off transition of the Resume switch will activate cruise.If, since the last ECM power up, cruise control was never active and the Resume switch goes from On/Off, the cruise target speed will be set to the actual veh spd.But if Cruise was active before, the Cruise Target Speed will be set to the last Cruise Set Speed, which will be lost during an ECM power cycle.As long as Cruise stays active, any other On/Off, Off/On or hold transition of the resume switch will be ignored.The Resume switch is only used to activate Cruise, set the old set speed = cruise target speed, ifnot 0, and enable the Accel and Decel switch.

15.1.4 Cruise Control Accel Switch Accel switch (PGN 65265 ($FEF1) Byte 5,bits 8,7 set to 01)

As long as the Cruise switch is Off and cruise is not active (by Set or Resume), the Accel switch has no functionality for the cruise feature.If cruise is active (Cruise on, Set or Resume On/Off transition, all other conditions are met –Veh spd, Clutch, Brake, Neutral, Cruise Pause), an Off/On transition of the Accel switch, whichlasts longer (ON) than 1.26 seconds (Hold), will cause the cruise target speed to ramp UP, by a fixed ramp rate.When the Accel switch is released (On/Off) the cruise target speed will be set to the current veh spd.If the holding time after the Off/On transition is shorter than 1.26 seconds (Bump), then the cruise target speed will be INCREASED by 1 mph (1.6 km/h).The Resume or Set switch must be On to enable the Accel or Decel switch function. NOTE: The Accel switch is not dependent on the Cruise/Idle/PTO switch configuration parameter.

15.1.5 Cruise Control Decel Switch Decel switch (PGN 65265 ($FEF1) Byte 5,bits 4,3 set to 01)

As long as the Cruise switch is Off and cruise is not active (by Set or Resume), the Decel switch has no functionality for the cruise feature.If Cruise is active (Cruise on, Set or Resume On/Off transition, all other conditions are met –Veh spd, Clutch, Brake, Neutral, Cruise Pause), an Off/On transition of the Decel switch, whichlasts longer (ON) than 1.26 seconds (Hold) will cause the cruise target speed to ramp DOWN, by a fixed ramp rate.When the Decel switch is released (On/Off) the cruise target speed will be set to the current veh spd.Ifthe holding time after the Off/On transition is shorter than 1 second (Bump), then the cruise target speed will beDECREASED by 1 mph (1.6km/h).The Resume or Set switch must be On to enable the Accel or Decel switchfunction. NOTE: The Decel switch is not dependent on the Cruise/Idle/PTO switch configuration parameter.

Priority

Set has a higher priority than Resume if both switch inputs are received at the same time. Accel has a higher priority than Decel if both switch inputs are received at the same time.

15.1.6 Cruise Pause Switch PGN (65265 ($FEF1) Byte 1,bits 6,5 set to 01) (J1939 input only)

The Cruise Pause switch will disable (kick out) cruise control (if active) and will prevent Cruise from being engaged if the switch is turned.The switch is independent from the Ignore Brake/Clutch switch status and it will not affect any timer functionality (Idle Shutdown and PTO Shutdown).This switch will act like the service brake or clutch switches can cause PTO or Extended Idle to kick out.If in the ON position, this switch will prevent the engine from entering into PTO mode or Extended Idle.

15.2 Service Brake Switch (PGN 65265 ($FEF1) Byte 4 Bits 6,5)

The Service Brake Switch input will respond to an Off to On transition and the ECM will respond the same as to hardwired switch inputs.This includes all features that respond to the Service Brake Switch #1 input (Cruise Control, Extended Idle, PTO, exhaust brake, etc.).

15.3 Clutch Switch (PGN 65265 ($FEF1) Byte 4 Bits 8,7)

The Clutch switch input will respond to an OFF to ON transition and the ECM will respond the same as to hardwired switch inputs.This includes all functions that respond to the Clutch Switch input (Cruise Control, Extended Idle, PTO, exhaust brake, etc.).

15.4 Fan Override Switch (PGN 65213 ($E000) Byte 1 Bits 8-1)

The Fan Override Switch may be programmed to None (Default), J1939 Cab Controller, J1939 Body Controller or J1939 Instrument Cluster.When the received message => 95.2% (switch ON), the ECM will turn J1/P1:11 OFF which will turn the fan ON.When the received message <= 94.8%, the ECM will control the fan according to engine conditions. The ECM will also support the Fan Override Switch message when broadcast from the transmission. Thetransmission may require that the fan be engaged to cool the transmission fluid during vehicle operatingconditions that result in high transmission loads.

15.5 Exhaust Brake Switch (PGN 61441 ($F001) Byte 5 Bits 8-1)

Exhaust Brake Switch may be programmed to None (Default), J1/P1:16, J1939 Cab Controller, J1939 Body Controller or J1939 Instrument Cluster.When programmed to one of the J1939 inputs the received message mustbe => 95.2%, before the Engine Exhaust Brake can be enabled.

15.6 Engine Diagnostic Switch (PGN 65265 ($FEF1) Byte 8 Bits 6,5)

Engine Diagnostic Switch may be programmed to None (Default), J1/P1:46, J1939 Cab Controller, J1939 Body Controller or J1939 Instrument Cluster.When programmed to one of the J1939 inputs and the ECM receives an On/ Off message transition, the ECM will enter into Diagnostic Mode and will cause the hardwired Check Engine Lamp to flash active Error codes.

15.7 Transmission Neutral Switch

The Transmission must support the J1939 PGN $F005 (ETC2 – Byte 1 – Selected Gear, Byte 4 – Current Gear orByte 7 – Current Range) message to be compatible.Selected gear and Actual Gear must be 0 when the transmission is in Neutral.If the message is not received, the ECM will assume the transmission to be in gear.