New Holland Workmaster 50, Service Manual

Page: 863 / 1067

Electrical systems - FAULT CODES
DTC 1F7-04-PMCat inlet temperature sensor voltage is lower than
expected
Control Module : ECU
Context:
The Engine Control Unit (ECU) A-9000 monitors the Particulate Matter (PM) catalytic converter inlet temperature sen-
sor B-9127. If the ECU A-9000 detects a voltage less than
459.40 mV in the PM catalytic converter inlet temperature
sensor B-9127 signal circuit, this fault will occur. If this fault is active, the last valid temperature value will be frozen
for a preliminary failure or set to a fixed replacement value of
99.96 °C ( 211.93 °F ) if the failure is validated.
Cause:
The ECU A-9000 has detected a voltage less than 459.40 mV in the PM catalytic converter inlet temperature sensor
B-9127 signal circuit.
Possible failure modes:
1. Faulty PM catalytic converter inlet temperature sensor B-9127 wiring, short to ground condition.
2. Faulty PM catalytic converter inlet temperature sensor B-9127, internal failure.
3. Faulty ECU A-9000, software.
Solution:
1. Verify fault is present and active.
Use the Electronic Service Tool (EST) to check the status of this fault.
A. If the fault is present and active, continue with Step 2 .
B. If the fault is no longer present or in an inactive state, the fault may be intermittent and not currently active.
Continue with Step 5 .
2. Check the PM catalytic converter inlet temperature sensor B-9127 for an internal failure.
Disconnect the vehicle harness from the PM catalytic converter inlet temperature sensor B-9127 at connector
X-9127 .
Use a multimeter to measure the resistance on the PM catalytic converter inlet temperature sensor B-9127 pins :
From To Value
X-9127 pin 1 X-9127 pin 2 There should be between 170.2 -
849.7 Ω .
A. If there is between 170.2 - 849.7 Ω , leave connector X-9127 pin 2 disconnected and continue to Step 3 .
B. If there is between 170.2 - 849.7 Ω , the PM catalytic converter inlet temperature sensor B-9127 has failed.
Replace the PM catalytic converter inlet temperature sensor B-9127.
3. Check the PM catalytic converter inlet temperature sensor B-9127 vehicle harness (VE) wiring for a short circuit
condition.
With the key in the OFF position, use a multimeter to perform the following continuity check on vehicle harness
(VE) side :
From To Value
X-9127 pin 2 X-9127 pin 1 There should be no continuity.
X-9127 pin 2 Chassis ground There should be no continuity.
A. If there is continuity, there is a short circuit in the PM catalytic converter inlet temperature sensor B-9127 ve-
hicle harness (VE) wiring. Use the appropriate service manual, if necessary, to locate and repair the shorted
conductor.
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