The following list is intended to offer a glimpse into the functions available for vehicles equipped with the Isuzu 4H and 6H diesel engines. Having the ability to change ECM parameters to fit many up fitter and customer needs is important. Many of these come with a preset value from the factory which requires changes for some body manufacturers. In the following list you will see a short explanation of each major electronic parameter within the ECM.
Isuzu 4H and 6H Engine ECM Parameters
Stationary Preset PTO
One of three power take off modes used to allow up to four preset engine speeds in Park or Neutral.
Stationary Variable PTO
One of three power take off modes used to allow variable engine speeds in Park or Neutral.
Mobile Variable PTO
One of three power take off modes used to allow variable engine speeds in and out of gear and with or without vehicle speed.
High Idle Switch Option PTO (6H Only)
This option allows raising the engine speed designed to aid in faster engine warm-up using a dash mounted switch.
High Idle Switch Engine Speed (6H only)
The preset engine speed for the High Idle Switch Option PTO
PTO Standby Speed
The engine speed used to notify the driver just after the PTO main switch has been turned ON. This speed can also be used to operate the PTO.
PTO Max. Engine Speed
Maximum allowed engine speed in PTO mode regardless of accelerator pedal input.
PTO Max. Vehicle Speed
Maximum vehicle speed allowed in PTO mode.
PTO Engage Relay
This feature allows the control of a relay in PTO mode when certain adjustable parameters have been met.
PTO Max. Engage Speed
Maximum engine speed for PTO hydraulic pump protection before the PTO Engage Relay will be activated.
PTO Feedback
An input used for PTO hydraulic pump protection which ensures the PTO Engage Relay has energized before allowing the engine speed to be raised.
PTO Engine Shutdown with Circuit Input
A safety feature which allows immediate engine shutdown-when the engine shutdown circuit is grounded in PTO mode.
PTO Shutdown with Circuit Input
A safety feature which allows the engine to return to base idle speed when a circuit is grounded in PTO mode.
PTO Shutdown Vehicle Speed
A safety feature which turns OFF the PTO Engage Relay above the programmed vehicle speed.
PTO Engine Shutdown Time Delay
The time between when the Engine Shutdown input is detected and the engine actually shuts down.
Disable Cab Controls
An option to disable the cruise control switches and accelerator pedal inside the cab in PTO mode.
Disable Cab Controls with Circuit Input
An option to disable the cruise control switches and accelerator pedal inside the cab in PTO mode with the disable cab control circuit switched to ground.
Diesel Particulate Filter (DPF) Regeneration in PTO
Allows Diesel Particulate Filter regeneration in Mobile Variable PTO mode.
PTO Brake/Clutch Override
Allows continuous PTO engine speed control with the brake pedal applied, which normally would cancel PTO in t he DDE Group.
Park Brake PTO Enable
An option to need the park brake enabled in order to raise the engine speed beyond the PTO Standby Speed.
PTO Set Speed
The first preset engine speed in Stationary Preset PTO mode when the cruise control set/resume switch is depressed.
PTO Resume Speed
The second preset engine speed in Stationary Preset PTO mode when the cruise control resume/accel switch is depressed.
PTO Increase RPM Rate
The engine speed increase amount in Stationary or Mobile Variable PTO mode when the cruise resume/accel switch is depressed.
PTO Reduce RPM Rate
The engine speed decrease amount in Stationary or Mobile Variable PTO mode when the cruise set/coast switch is depressed.
PTO Accel RPM Rate
The rate at which the engine speed changes when using the cruise control or remote switches.
Remote PTO Set/Resume Switches
This option enables the use of Remote PTO Set/Resume Switches for both Variable PTO modes.
Remote PTO Set Speed AB Switches
This option enables the use of the remote PTO Set AB Switches for the Stationary Preset Mode.
Remote PTO Set Speed A
This is the preset engine speed in Stationary Preset PTO mode when the remote Set Speed A switch is depressed.
Remote PTO Set Speed B
This is the preset engine speed in Stationary Preset PTO mode when the remote Set Speed B switch is depressed.
Remote PTO Throttle
This option enables the use of a throttle type potentiometer to vary engine speed in all PTO modes.
Remote PTO Throttle 0%
This indicates the lower voltage limit for the throttle potentiometer at the minimum or 0% throttle position.
Remote PTO Throttle 100%
This indicates the upper voltage limit for the throttle potentiometer at the maximum or 100% throttle positioning.
Remote PTO Throttle Max. Engine Speed
Maximum allowed engine speed when using Remote PTO throttle regardless of accelerator pedal input.
PTO Operation Hours Reset (6H Only)
The function resets the logged engine running hours while in PTO mode.
Cruise Control
Cruise Control Disable
This option locks out the use of cruise control.
Minimum Cruise Control (DDE Group)
Minimum allowed cruise control set speed
Maximum Cruise Control
Maximum allowed cruise control set speed
Relaxed Cruise Control (DDE Group)
Allows the cruise control system to deviate up to 5 mph while in cruise control to reduce transmission gear hunting.
Exhaust Brake
Exhaust Brake Mode
This option allows three modes during Exhaust Brake activation: Manual, Coast, and Latch.
Exhaust Brake Latch Mode Engine Speed
The minimum engine speed allowed for the exhaust brake activation in the exhaust brake latch mode.
Exhaust Brake in Cruise
Allows the engine controller to utilize the exhaust brake in cruise control to slow the vehicle down.
Exhaust Brake in Cruise ON Speed
The minimum vehicle speed threshold in which the exhaust brake in cruise is allowed to operate.
Exhaust Brake in Cruise OFF Speed
The maximum vehicle speed threshold in which the exhaust brake in cruise is allowed to operate.
Exhaust Brake Time Delay
The time between when the engine controlled would be commanding the exhaust brake on to when the exhaust brake is actually turned on.
Vehicle Speed Limit
Vehicle Speed Limit
Maximum allowable vehicle speed limit.
Vehicle Speed Output Pulses per Mile
An option to allow the engine controller to transmit a square wave signal which represents the actual vehicle speed (DDE Group only)
Tachometer Output Pulses per Engine Revolution
An option to allow the engine controller to transmit a square wave signal which represents the actual vehicle speed.
Engine Idle Speed
Base Idle Speed (6H only)
This option allows the base idle speed to be raised within a certain range.
Coolant Conditions
Engine coolant warm-up when the engine coolant is below a certain threshold.
Engine Oil Life
Engine Oil Life Enable (6H only)
This option allows the enable or disable of the engine oil change lamp algorithm.
Engine Oil Capacity (6H only)
This option allows the accommodation of additional oil capacity due to the Luber-Finer option.
Engine Shutdown
Controlled Engine Shutdown
Engine shutdown available due to high engine temperature, low coolant level, or abnormal oil pressure (either high or low oil pressure)
Engine Protection Counter – Engine Overspeed
Tied to Controlled Engine Shutdown
Engine Protection Counter – High Exhaust Temp
Tied to Controlled Engine Shutdown
Engine Protection Counter – High EGR Temp
Tied to Controlled Engine Shutdown
Engine Shutdown Counter – Low Oil Level
Tied to Controlled Engine Shutdown
Engine Shutdown Odometer – Low Oil Level
Tied to Controlled Engine Shutdown
Engine Shutdown Counter – Low Coolant Level
Tied to Controlled Engine Shutdown
Engine Shutdown Odometer – Low Coolant Level
Tied to Controlled Engine Shutdown
Engine Shutdown Counter – High Coolant Temp
Tied to Controlled Engine Shutdown
Engine Shutdown Odometer – High Coolant Temp
Tied to Controlled Engine Shutdown
Gear Down Protection (6H with Manual Transmission Only)
Gear Down Protection Engine Speed Limit Enable
Forces earlier shifting to create better fuel economy.
Gear Down Protection Engine Speed Limit
Forces earlier shifting to create better fuel economy.
Gear Down Protection Turn ON Speed
Forces earlier shifting to create better fuel economy.
Low Gear Engine Speed Limit Enable
Forces earlier shifting to create better fuel economy.
Low Gear Engine Speed Limit
Forces earlier shifting to create better fuel economy.
Low Gear Turn OFF Speed
Forces earlier shifting to create better fuel economy.
Intermediate Engine Speed Limit Enable
Forces earlier shifting to create better fuel economy.
Intermediate Engine Speed Limit Enable
Forces earlier shifting to create better fuel economy.
Intermediate Gear Engine Speed Limit Enable
Forces earlier shifting to create better fuel economy.
Intermediate Gear Turn OFF Speed
Forces earlier shifting to create better fuel economy.
