New Holland WorkMaster 50 Service Manual page 937

DTC 3F6-03-DOC inlet temperature sensor voltage is higher than
expected
Control Module : ECU
Context:
The Engine Control Unit (ECU) A-9000 monitors the Diesel Oxidation Catalyst (DOC) inlet temperature sensor B-9127.
If the ECU A-9000 detects a voltage greater than 3.59 V in the diesel oxidation catalyst inlet temperature sensor
B-9127 signal circuit, this fault will occur.
Cause:
The ECU A-9000 has detected a voltage greater than 3.59 V in the diesel oxidation catalyst inlet temperature sensor
B-9127 signal circuit. For more information regarding the technical specifications of the DOC inlet temperature sensor
B-9127, see Exhaust Gas Recirculation (EGR) temperature sensors - Technical Data (55.989).
Possible failure modes:
1. Faulty DOC inlet temperature sensor B-9127 wiring, short to voltage source.
2. Faulty DOC inlet temperature sensor B-9127 wiring, open circuit.
3. Faulty DOC inlet temperature sensor B-9127, internal failure.
4. 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 6.
2. Check the DOC inlet temperature sensor B-9127 for an internal failure.
Disconnect the vehicle harness (VE) from the DOC inlet temperature sensor B-9127 at connector X-9127.
Use a multimeter to measure the resistance on the diesel oxidation catalyst inlet temperature sensor B-9127 :
From
X-9127 pin 1
A. If there is between 170.2 - 849.7 Ω, leave connector X-9127 disconnected and continue to Step 3.
B. If there is not between 170.2 - 849.7 Ω, the diesel oxidation catalyst inlet temperature sensor B-9127 has failed.
Replace the DOC inlet temperature sensor B-9127.
3. Check the DOC inlet temperature sensor B-9127 vehicle harness (VE) wiring for a short circuit.
With the key in the OFF position, use a multimeter to perform the following voltage check on the vehicle harness
side :
From
X-9127 pin 1
A. If there is voltage, there is a short to battery in the diesel oxidation catalyst inlet temperature sensor B-9127
wiring. Use the appropriate service manual, if necessary, to locate and repair the shorted conductor.
B. If there is no voltage, leave connector X-9127 disconnected and continue to Step 4.
Electrical systems - FAULT CODES
To
X-9127 pin 2
To
Chassis ground
47866583_ 02/12/2015
55.12 [55.DTC] / 216
Value
There should be between 170.2 -
849.7 Ω.
Value
There should be no voltage.