New Holland T8010 Manual page 1510

PTO RPM Is Too High
Cause:
The PTO controller monitors the PTO clutch input and output speed. This fault code is recorded when the PTO
controller has detected a PTO speed that is 20% higher than expected for more than 2 seconds.
Possible failure modes:
1. PTO load is driving the PTO.
2. Wrong signal from the shaft speed sensor.
3. Incorrect alternator installed
PTO SHAFT SPEED SIGNAL
The PTO shaft speed frequency is derived from a variable reluctance speed sensor in the transmission. The clutch
speed sensor is connected directly to the PTO control module in all versions of the PTO control system. The
sensor output is directly proportional to PTO clutch output speed, and is a quasi-sinusoidal wave form the
amplitude of which is non-linearly proportional to speed. The amplitude range of the signal is from 3 volts peak-to-
peak to 80 volts peak-to-peak centered around chassis ground. Frequency range is from zero to 3,200 Hz worst
case.
PTO SHAFT SIZE SPEED SIGNAL
The PTO shaft size speed frequency is derived from a variable reluctance speed sensor in the transmission. The
sensor is connected directly to the PTO control module and its output is proportional to PTO clutch output speed,
but scaled differently from the PTO clutch speed signal depending upon which PTO shaft is in use; i.e. 1-3/4" 1000
RPM, 1-3/8" 1000 RPM or 1-3/8" 540 RPM. The signal is a quasi-sinusoidal waveform the amplitude of which is
non-linearly proportional to speed. The amplitude range of the signal is from 3 volts peak-to-peak to 80 volts peak-
to-peak centered around chassis ground. Frequency range is from zero to 760 Hz worst case.
Solution:
Make sure the PTO shaft is not driven by the load such as in the down hill situation.
Test the PTO speed sensor and its wiring harness.
1. Check the PTO operation is correct and the external load is not driving the shaft.
2. Check the wiring harness to the PTO shaft speed sensor.
Check the continuity from Pin 20 of connector C058 to Pin A of connector C145.
Check the continuity from Pin B of connector C145 to the chassis ground.
3. Check the function of the PTO speed sensor. It should have resistance of about 3 K ohms.
4. Check the alternator and the engine RPM signal from the alternator.
The PTO clutch input speed is the engine RPM signal from the alternator.
a. Make sure the alternator is the correct model. Incorrect alternator will give wrong signal frequency which
may trigger this fault code.
b. Check for worn alternator belt.
c. Check the engine RPM signal wiring. There should be good continuity between cavity 33 of AUX/Hitch/PTO
controller connector C057 and the terminal W of the alternator.
d. Check the engine RPM signal at terminal W of the alternator.
e. Go to the monitor screen of the service tool. Select parameter PTO ENGINE SPEED FREQUENCE. This is
the PTO clutch input speed.
NOTE: Always inspect connector ends for damaged, bent or dislocated pins when troubleshooting.
NOTE: See schematic sections 49 and 50 on the schematic poster.
Section 55 - Electrical System, Controller - Chapter 3
AUX/HITCH/PTO FAULT CODE 161
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55-3-91