Idle/Throttle Speed Control Unit: Description and Operation

New Stationary Elevated Idle Control for 2005 Model Year Light Trucks

Models Affected 2005 Model Year F-250/350/450/550 and E-250/350/450.

Purpose

To introduce the new stationary elevated engine idle speed control system for power take-off applications, including related customer access signal circuits and pass-thru circuits.

Overview

SEIC strategy

- Provides elevated engine speed to drive auxiliary commercial equipment such as hydraulic pumps, generators, air compressors; or maintain vehicle battery charge under extreme electrical demands.
- Standard in all PCM's for Super Duty F-Series light truck, and E-Series, over-8500 lb. GVWR, all powerirains.
- Replaces the Auxiliary Powerirain Control Module (APCM) used with 2004 model year and prior diesel engines.

Blunt-cut wires to access SEIC, and customer access for VSO, CTO, PARK, PARK-NEUTRAL signals.

- F-Series: Located in the cabin, tagged and bundled above the parking brake pedal assembly. Pass-thru wires are in the same bundle.
- E-Series: In the engine compartment, tagged and bundled with the large harness running below the windshield/cowl. Remove some ot the plastic harness tape where the harness exits its plastic support gutter above the engine air induction tube to reveal the blunt-cut wires.
- The final stage manufacturer or up-fitter is required to supply the customer interiace or controller.
- Further detailed in the "Circuit Descriptions" section.

Blunt-cut wires to access the four optional Up-fitter Switches.

- Available as an option on Super Duty F-Series only, Option Code 66S.
- May be used as a PTO activation switch.
- Located in the cabin, above the parking brake pedal assembly. Remove the PDJB for easy access.
- Further detailed in the "Circuit Descriptions" section.

Transmission PTO gear and port.

- Available for Super Duty F-Series only.
- Standard with M6OD 6-speed manual transmission.
- Available for TorqShift 5-speed automatic transmission by ordering Transmission Power Take-Off Provision, Option Code 62R.






Product Descriptions

SEIC (Stationary Elevated Idle Control): New for 2005 model year, this feature is included in the powerirain control strategy of all F250/350/450/550 and E250/350/450, over-8500 lb GVWR, all powerirains. For diesel engines it replaces the APCM (Auxiliary Powerirain Control Module) previously included with Ford "Auxiliary Idle Control Kit" Option Codes 96P (F-Series) and 961 (E-Series). For a stationary vehicle it allows the operator to elevate engine idle speed to operate a transmission-mounted PTO, or engine FEAD-mounted clutch-pump, air compressor, or generator; or be used to help keep the vehicle battery charged. SEIC uses CAN messaging internally. It is activated by applying discrete voltage signals to a wire bundle located in the F-Series cabin above the parking brake release handle, and in the E-Series engine compartment. The up-fitter will need to complete the circuits as described herein, and provide the customer interiace (i.e. buttons, LCD read-out for engine speed, PlO switch, etc.). Note: The F-Super Duty light truck offers four optional relayed rocker switches on the instrument panel for the up-fitter to use (Option Code 66S). Ramp-up rate is fixed and approximately 200 rpm/sec for diesel engine and 400 rpm/sec for gas engine.

PTO Control (For automatic transmission-mounted PTO only): This is PCM strategy within the SEIC feature that automatically looks for and recognizes whether the vehicle has a TorqShift automatic transmission with a side- mount PTO ("Transmission PTO Provision", Option Code 62R), and makes the internal PTO gear function by commanding the torque converter to lock at 1200 rpm minimum speed. The PTO gear is splined directly to the transmission torque converter turbine shaft. When all of the vehicle safety enablers are met, and the engine speed is commanded by the operator to at least 1200 rpm, then the strategy automatically commands the torque converter to lock at 1200 rpm to deliver engine torque to the PTO gear (actual lock-up begins at approximately 1050 rpm), and elevates the transmission hydraulic line pressure to 150 psi nominal for the aftermarket PTO to use to hold its engagement clutch. NOTE: Applying battery voltage to the Diesel "PTO" or Gas "PTO-Mode" wires is required to initiate these commands. Failing to do so may show up as low or oscillating hydraulic line pressure and low or no aftermarket PTO torque or pump flow output. Any attempt to operate the aftermarket PTO at elevated idle without these commands may result in under-capacity PTO clutch wear, resulting in rapid contamination of transmission fluid and internal transmission damage. This applies to both stationary - mobile automatic transmission PTO operations.

Circuit Descriptions for SEIC and Customer Access Signal Circuits

All circuits lead back to pins on the PCM.


















Battery Voltage Sources (VPWR)






SEIC Resistor Charts






SEIC Enable/Disable Conditions






Note-1: A "change-of-state" at the "PTO-Request" circuit is required to re-invoke SEIC.

When a disabler is seen by the PCM the "PTO-lndicator" circuit changes from "ground-source" to "open-circuit". After approximately 3 seconds SEIC drops out, returning the engine speed to base idle. For vehicle-stationary operation, the automatic transmission torque converter unlocks as engine speed proceeds below 1200 rpm. To re-initiate SEIC the operator must turn off the aftermarket PlO switch (removing command voltage to the "PTO-Mode circuit) and turn it back on again.

Note-2: SEIC is automatically re-activated after approximately 3 seconds after the disabling condition is removed.

SEIC / PTO - General System Behavior

^ To guarantee full advertised torque capability at the automatic transmission PlO gear, and through the aftermarket PlO clutch, the transmission torque converter must be locked, and the hydraulic line pressure serving the aftermarket PlO clutch must be elevated. Applying battery voltage to the PlO circuit is the signal to the transmission to enter SEIC strategy and command these two important functions. This applies to both stationary and mobile PTO operations.

^ If an SEIC disabler occurs:
- GAS engines will require a "change-of-state", meaning the operator is required to turn off voltage to the "PTO-Request circuit, and back on again to re-invoke SEIC and PTO operation.
- DIESEL engines do not require a "change-of-state" at the "PTO" circuit. Once the disabling condition is removed, the strategy re-invokes SEIC after approximately 3 seconds, automatically returning the engine speed back to what was commanded by the operator prior to the disabling condition.

^ Battery Charge Protection (BCP): A diesel-only function. When it is switched on the engine speed goes immediately to 1200 rpm, and stays there even if the battery is fully charged. From this state it uses system voltage as well as ambient air temp., engine oil temperature information to raise engine speed higher to maintain a certain battery charge. Maximum engine speed in BCP mode is 2400 rpm. The BC PSW circuit may be wired to circuit to Ignition-Hot-in-Run to make it "automatic" for ambulance. Park-Brake-Set is one of the enablers of BCP.

^ If the Transmission Oil Temperature (TOT) sensor reaches 240°F, then TorqShift torque converter may disengage, preventing torque to be delivered to the transmission PTO gear.

^ SEIC/PTO strategy function in the PCM is not affected by the loss of vehicle battery electrical power.

^ SEIC Ramp Rate (fixed, not programmable):

- GAS engines: 400 rpm/second.
- DIESEL engines: When first applying battery voltage to the PTO circuit the PCM directs the engine to go to the initial target that it sees at the RPM circuit at 200 rpm/second (1200 rpm if there is no resistor in the RPM circuit - open circuit). If resistance is subsequently changed at the RPM circuit then the ramp rate to this second speed target is virtually instantaneous (as fast as the diesel engine can get there).

^ Correlation between engine speed and resistor values:

- The external voltage source that the aftermarket PTO system designer uses to command SEIC through the "PTO" or "PTO-Request" circuits must be the same as that used by the PCM internally for predictable SEIC function. Reasoning is that a fully-charged vehicle battery fluctuates with ambient temperature.
- The correlation will be better for diesel engines since the diesel engine SEIC system offers buffered PCM voltage and ground circuits to complete the resistor circuits for engine speed, while the gas engine system forces the SEIC circuit installer to use chassis voltage and ground.
- If there is a high electrical demand on the chassis battery, such as from aftermarket inverters or generators, etc., the actual elevated idle engine speed may vary with that demand for any given resistance in the SEIC circuit. More so for gas engine systems than diesel since gas engine uses chassis battery voltage as a reference.

^ GAS Engine Only:

- Normal base engine calibration allows approximately +/-50 rpm fluctuation. If any factory vehicle accessories are used during SEIC, e.g. a/c, defroster, etc., then that fluctuation may increase to approximately +/-1OO rpm or more.
- The sudden loss of aftermarket PTO hydraulic pressure during SEICIPTO operation, like a ruptured hose, may send SEIC engine speed to near 3000 rpm. It is recommended that a hydraulic pressure switch linked to SEIC/PTO be added to disable SEIC/PTO when a hose ruptures.
- Because of a service brake circuit characteristic at engine-start, invoking SEIC may cause the diagnostic error code FFG_BOO to get flagged (recorded in the PCM). To avoid this, simply tap the service brake pedal sometime after engine-start and prior to invoking SEIC. Once the code is set, SEIC may not be available until it is erased.
- Gas engines require a "change-of-state" at the PTO-Mode and PTO-Engage circuits whenever a disabler turns off SEIC (remove battery voltage signal and re-apply).
- For aftermarket remote engine start-stop: a change-of-state is required to get SEIC to function again.