1999/10/18 Caterpillar

776D (5ER),
784B (5RK) Tractors;
771D (6JR),
775D (6KR) Quarry Trucks;
769D (5TR),
773D (7ER),
777D (3PR),
777D HAA (2YW),
785B (6HK),
789B (7EK),
793C (4AR) Off-Highway Trucks

Description of Change:

An improved Automatic Retarding Control (ARC) for off-highway trucks is available. The new control improves the response to changing ground speeds to reduce the possibility of engine overspeed conditions. Diagnostic controls have been improved to reduce the possibility of generating operator induced diagnostic codes.

A new lamp test feature turns the ARC lamp on for three seconds when the key is turned on replaces the previous open circuit diagnostics for ARC indicator lamp. Removing the open circuit diagnostic from the ARC indicator allows the use of an LED lamp for the ARC indicator. The only way to determine that the ARC indicator lamp is burnt out is to watch for the three second lamp test at Key-On.

The new 164-6159 Control Group is a direct replacement for the former 130-5806 Control Group.

The following is a summary of the improvements of the new Automatic Retarding Control (ARC) group.

* Brake air given full pressure for up to one second at initial ARC activation to speed brake system response.

* Throttle lockout is increased from 3% throttle to 60% throttle.

* Throttle ON protection RPM is lowered to 2125 RPM from 2180 RPM.

* Diagnostic debounce time is increased to compensate for operational conditions.

* ARC lamp diagnostics are removed and replaced with a 3 second lamp test at KEY-ON.

Adaptable To: The new 164-6159 Control Group is adaptable to 776D (5ER1-Up), 784B (5RK1-Up), 771D (6JR1-Up), 775D (6KR1-Up), 769D (5TR1-Up), 773D (7ER1-Up), 777D (3PR1-Up), 785B (6HK1-Up), 789B (7EK1-Up), 793C (4AR1-Up).

Effective With: The new 164-6159 Control Group is effective with 776D (5ER128), 777D (3PR1067), 777D HAA (2YW106).