CAP 6C8996 - Caterpillar

System Operation Description:The engine retarder solenoids are usually factory installed at Caterpillar and the switches are installed by the vehicle OEM. The ECM directly drives the retarder solenoids, eliminating OEM installed relays and circuit protection. The ECM reads the status of the OEM installed engine retarder switches in order to determine the following modes of operation:
OFF
Low
Medium
HighOperation of the retarder solenoids is inhibited during undesirable engine operating conditions. All of the following conditions must be met in order to ensure the proper retarder operation regardless of the settings of the customer specified parameters:
Engine speed is above 800 rpm.
The "Accelerator Pedal Position" is less than 8 percent.
The clutch pedal is released.Additional factors may affect retarder operation. The additional factors are based on the programming of certain customer specified parameters. The following parameters may affect retarder operation:
"Engine Retarder Mode"
"Auto Retarder In Cruise"
"Auto Retarder In Cruise Increment"
"Engine Retarder Minimum Vehicle Speed"
"Engine Retarder Minimum Vehicle Speed Type"
"Engine Retarder Delay"Note: If the "PTO Configuration" is programmed to Cab Switches, Remote Switches, or Remote Throttle, the engine retarder is disabled whenever the PTO On/Off circuit is on.When the Cruise Control On/Off Switch is in the ON position, the following conditions exist:"Engine Retarder Mode"When the cruise control On/Off switch is on, this parameter provides two special options that allow the engine retarder to be operated only after the driver has depressed the service brake pedal. The two modes of operation that follow are customer programmable:
The "Coast" mode engages the engine retarder when the driver depresses the service brake pedal. The retarder disengages when the driver releases the service brake pedal.
The "Latch" mode engages the retarder when the driver depresses the service brake pedal. The retarder remains engaged until the control detects a change in a control input. The following actions are examples of a change in a control input:
The throttle is depressed.
The clutch pedal is depressed.
The engine speed drops below 800 rpm.The third option for the engine retarder parameter is "Manual". The Manual mode operates in the same manner regardless of the position of the cruise control On/Off switch. The driver is not required to depress the service brake pedal in order to initiate the engine retarder. This is required in the Latch mode and the Coast mode.Note: The Latch mode and the Coast mode are customer programmable options. The Latch mode and the Coast mode determine engine retarder operation only when the cruise control switch is in the ON position. The Latch mode and the Coast mode do not determine engine retarder operation when the engine is active in cruise control. Latch mode and Coast mode require the initiation of the service brake before acting. The action of the service brake disengages the cruise control."Auto Retarder In Cruise"This parameter allows the engine retarder to activate while the engine is in cruise control in order to maintain the cruise set speed. The "Auto Retarder in Cruise" option still requires the engine retarder switches to be in the ON position. The "Auto Retarder in Cruise" option will