1998/06/01 Caterpillar

C-10 (8YS),
C-12 (9NS),
3406E (1LW, 5DS) Truck Engines In Applications With A Horton 3-Speed Fan

One feature of the FEB98 Heavy Duty Truck Engine Software release is the support of "Horton 3-Speed Fan". This feature allows the engine Electronic Control Module (ECM) to control the operation of this fan. The Horton 3-Speed Fan operates in three modes: "Brake", "Slip", and "Direct" (full speed). Of the three modes, the "Slip" mode is used most of the time. The fan will require an additional output driver from the engine ECM. The two selected ECM drivers together will control two air solenoids which control the fan mode (speed). The ECM has non-programmable conditions to determine the operation of each mode (speed) dependent upon water temperature and inlet manifold air temperature.

The ECM uses Multi-Function Output numbers 3 and 4 (MF#3 and MF#4) for driving the two solenoids. The set logic for the three modes (speeds) is as follows:

* Both MF#3 and MF#4 (ON) = Brake Mode (Zero Speed)

* MF#3 (OFF) and MF#4 (ON) = Slip Mode

* Both MF#3 and MF#4 (OFF) = Direct Mode (Full Speed)

The minimum ON time for Direct Mode is 20 seconds and minimum ON time for Slip Mode is 3 seconds. If the Air Conditioning pressure switch is active, the minimum Direct Mode ON time does not apply.

If Fan In Retarder parameter is programmed to "Yes", the fan will operate at full speed when conditions are met. This will allow for maximum braking and the minimum ON time in the Direct Mode does not apply.

The Service Tool will need to have Fan Type programmed to Horton 3-Speed and set Multi-Function Output number 3 to Fan and Multi-Function Output number 4 to Cooling Fan. Failure to program these correctly will result in a 253-02 Diagnostic Code. This will also result in the fan operating in the Direct Mode (Full Speed) only.

In C-10 and C-12 Truck Engines, the ECM controls the fan operation by the following conditions:

* Below 80°C (176°F) Water and 0°C (32°F) Air = Brake Mode.

* Between 86 and 96°C (187 and 205°F) Water there is a hysteresis or hold in mode condition.

* Brake ON and Temperature rising to 91°C (196°F) Water, 54°C (129°F) Air = Brake Mode.

* Slip ON and Temperature falling to 80°C (176°F) Water and 0°C (32°F) Air = Slip Mode.

* 91 to 96°C (196 to 205°F) Water = Slip Mode.

* Above 96°C (205°F) Water, 82°C (180°F) Air with less than 70 kPa (10.2 psi) Boost = Direct Mode until 91°C (196°F) Water or 52°C (126°F) Air:

or

* Above 96°C (205°F) Water, 96°C (205°F) Air with less than 70 kPa (10.2 psi) Boost = Direct Mode until 91°C (196°F) Water or 52°C (126°F) Air.

In 3406E Truck Engines, the ECM controls the fan operation by the following conditions:

* Below 86°C (188°F) Water, 0°C (32°F) Air = Brake Mode.

* Between 86 and 96°C (188 and 205°F) Water there is a hysteresis or hold in mode condition.

* Brake ON and Temperature rising to 91°C (196°F) Water, 54°C (129°F) Air = Brake Mode.

* Slip ON and Temperature falling to 80°C (176°F) Water and 0°C (32°F) Air = Slip Mode.

* 96 to 102°C (205 to 216°F) Water = Slip Mode.

* Above 102°C (216°F) Water, 82°C (180°F) Air with less than 70 kPa (10.2 psi) Boost = Direct Mode until 91°C (196°F) Water or 52°C (126°F) Air:

or

* Above 102°C (216°F) Water, 96°C (205°F) Air with less than 70 kPa (10.2 psi) Boost = Direct Mode until 91°C (196°F) Water or 52°C (126°F) Air.