New Holland WorkMaster 50 Service Manual page 863

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
X-9127 pin 1
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
X-9127 pin 2
X-9127 pin 2
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.
Electrical systems - FAULT CODES
To
X-9127 pin 2
To
X-9127 pin 1
Chassis ground
47866583_ 02/12/2015
55.12 [55.DTC] / 142
Value
There should be between 170.2 -
849.7 Ω.
Value
There should be no continuity.
There should be no continuity.