PTO Electronic Operation

WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

During PTO operation, the Powertrain Control Module (PCM) receives a 12-volt input signal from the PTO circuitry at pin 4 for the 6.8L engine, or pin 66 for the 7.3L engine. The PTO installer must provide this signal circuit. The PCM uses this signal to disable self diagnostics and to monitor powertrain operation during PTO usage.

The PTO installer must provide an electronic throttle kicker on 6.8L engines that increase engine speed to 1300 RPM during PTO operation. As part of PTO operation for the 7.3L engine, the PCM automatically increases the engine speed to 1200 RPM. An auxiliary powertrain control module may be installed in the 7.3L engine applications for PTO operation at other engine speeds.

During PTO operation, the PCM turns ON the Coast Clutch Solenoid (CCS). This allows engine power to be transmitted through the transmission input shaft to the PTO drive gear on the coast clutch cylinder.

The PCM also operates shift solenoid SSB in the following manner during PTO operation:

P, R or N: ON (OFF without PTO)
First gear: OFF (OFF without PTO)
Second gear: ON (ON without PTO)
Third gear: ON (ON without PTO)

PTO operation can cause transmission fluid temperature to exceed the recommend maximum limit of 121 °C (250°F). The failure mode logic programmed in the PCM prevents transmission damage by disabling the PTO above this limit.