Sierra 1500 4WD V8-5.3L VIN B HO (2006)
Power Take-Off: Testing and Inspection
Power Take-Off (PTO) Does Not Engage
POWER TAKE-OFF (PTO) DOES NOT ENGAGE
CIRCUIT DESCRIPTION
This symptom table aids in the diagnosis of a failed power take-off (PTO) solenoid engagement. This diagnostic does not expose a mechanical
condition with the PTO itself. Voltage is supplied at all times through the cruise fuse to the secondary side of the relay. When the relay is energized,
the contacts close and current is allowed to flow to the PTO solenoid. The solenoid has its own external ground. When the ignition switch is in the
RUN position, voltage is present at the PTO switch. When the PTO switch is in the ON position, voltage is present at the coil of the relay and at the
PCM. If the PCM sees all of the conditions necessary to engage the solenoid, the PCM grounds the primary circuit of the relay.
TEST DESCRIPTION