1994/08/29 Caterpillar

768C (02X),
772B (64W),
776B (6JC),
776C (2TK) Tractors;
769C (01X),
773B (63W),
777B (4YC, 3NF),
777C (4XJ, 8JL),
785 (8GB),
785B (6HK),
789 (9ZC),
789B (7EK),
793 (3SJ),
793B (1HL) Trucks;
771C (3BJ),
775B (7XJ),
Quarry Trucks;
621E (6AB, 2PD),
621F (4SK),
623E (6YF, 6CB),
623F (6BK),
627E (6EB, 6GB, 7CG),
627F (1DL),
631E (1AB, 1NB, 3ND),
637E (1FB, 1JB),
651E (89Z),
657E (90Z, 91Z) Wheel Tractor-Scrapers

Reference: Service Manual Module, SENR5666, Electronic Programmable Transmission Control II (EPTC II) For ICM Transmissions.

Several changes have been made to the EPTC II control groups. The purpose of this article is to describe the significant changes and identify the various part numbers of the EPTC II control groups.

Tractors And Trucks

104-4287 Control Group-This control group provides the directional shift management function for most trucks, except later 776Bs and 777Bs. Directional shift management reduces the engine throttle setting briefly, when a shift out of neutral is made. This feature will work on earlier trucks only if the corresponding air solenoid valve and wiring are added.

3E-5191 Control Group-This control group provides the directional shift management function for all trucks, including later 776Bs and 777Bs.

110-7491 Control Group-This control group has the additional capability of providing the neutral start function, and can actuate the start solenoid directly. Not all models have the wiring changes to use this feature, and some still utilize the former neutral start system. If an earlier control group is installed on a machine that is wired for EPTC II neutral start, then the engine will not crank.

The 110-7491 Control Group has four additional status indicators within the display area. The additional indicators are:

Engine Speed

Torque Converter Output Speed

Body Up

Service Mode

The engine speed and torque converter output speed indicators will only operate if the necessary sensors and wiring are present. VIMS requires these two speed signals, for calculating the amount of clutch slippage. Therefore, these two indicators are functional only on machines equipped with VIMS.

118-2452 Control Group-This control group has the additional capability of providing the engine overspeed function for the 768C, 769C, 771C, 772B, 773B, and 775B. This feature allows the transmission to upshift one gear above the shift cane, if necessary, to reduce the chance of engine overspeed. If the transmission is in top gear, the torque converter lockup clutch will disengage. The engine overspeed feature will work on earlier machines, if a 118-2452 Control Group is installed.

NOTE: Some earlier machines did not have the engine overspeed warning system. The engine overspeed warning system flashes a lamp and sounds a horn before the transmission shifts above the shift cane position. If a 118-2452 Control Group is installed on an earlier machine that does not have the engine overspeed warning system, then the engine overspeed warning system should also be installed at the same time. This will alert the operator that an overspeed condition exists, before the transmission shifts above the shift cane position.

The body up gear limit function is now enabled at the factory for 769C, 771B, 773B and 775B Trucks. The feature works on earlier machines only if the machine is modified to include the body up switch and the associated wiring. Earlier controls contained this feature for these models, but it was not enabled at the factory. The feature can be enabled or disabled by using the service switches (set and clear) or by using the ECAP service tool.

On machines equipped with VIMS, the 118-2452 Control Group sends transmission clutch slip data to the VIMS. Later the data can be downloaded to a laptop computer.

The 118-2452 Control Group has the capability of activating the backup alarm. But, current machines have not yet been changed to utilize this feature.

Wheel Tractor-Scrapers

111-4043 Control Group-This control group has the capability of providing the neutral start function. F-Series machines have the necessary wiring to use this function. The E-Series machines used a different neutral start system. If the former 3E9234 Control Group is installed on an F-Series machine, the engine will not crank.

The 111-4043 Control Group has the capability of controlling the auger relay, if so equipped. The F-Series machines have the necessary wiring to use this function. The E-Series machines used a different auger control circuit.

The 111-4043 Control Group has four additional status indicators within the display area. The additional indicators are:

Engine Speed (not functional)

Torque Converter Output Speed (not functional)

Auger (so equipped F-Series machines)

Service Mode