236 • Section 10 — Chassis Information Cayman 2006
When the exhaust brake is activated, a fl apper inside the exhaust brake
moves and restricts the fl ow of exhaust gases. This causes an increase of
exhaust pressure within the engine. Increased exhaust back pressure quickly
slows the engine speed resulting in powerful engine braking action. When the
exhaust brake is activated, the amount of engine braking power developed is
related to engine speed (RPM). When an exhaust brake application is made, the
engine braking affect increases with higher engine RPM.
The exhaust brake is wired to the electronically controlled transmission.
When the exhaust brake is activated going down a hill, it will help control road
speed or suffi ciently slow the road speed until the Allison Transmission can
automatically downshift to the next lower gear. Downshifting automatically
occurs from high gear down to second gear. Certain road conditions and engine
speeds may require the transmission be manually shifted down in order to
generate adequate engine RPM and increase the engine brake effect.
NOTE:
The brake lights will illuminate while the Exhaust Brake is
applied.
NOTE:
Activating the Exhaust Brake switch will cancel the cruise control.
Maintenance
Contributing causes such as
moisture, dirt, carbon and improper
use can produce failure with the
exhaust brake.
Starting the engine and idling for short periods of time is not recommended.
Moisture is created within the engine and the exhaust system during cold
startups. When normal operating temperatures are not obtained, moisture may
get trapped in the valve housing resulting in rust and leading to insuffi cient
operation of the exhaust brake. To help prevent exhaust brake freeze-up caused
by periods of non-use, it is recommended to use silicone spray at the points
shown. Apply liberal amounts of silicone spray to the moving joints whenever
the motorhome is parked for storage. Use a pair of pliers to manually operate
the valve several times and work the lubricant into moving parts.
NOTE:
Do not use petroleum-based lubricants as these will burn off and
possibly create a fire hazard.
Problems related to electrical symptoms:
• Will not activate or deactivate.
• Intermittent ON/OFF operations.
• Actuates with the switch OFF.
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