New Holland WorkMaster 50 Service Manual page 747

DTC 135-03-Fuel temperature sensor voltage is higher than
expected
Control Module : ECU
Context:
The Engine Control Unit (ECU) A-9000 monitors the fuel temperature sensor B-9002 signal circuit voltage. If the ECU
A-9000 detects a voltage greater than 4.93 V in the signal circuit, this fault will occur. If this fault is not inhibited by
another fault, the ECU A-9000 will freeze the fuel temperature value to 39.96 °C (103.93 °F).
Cause:
The fuel temperature sensor B-9002 signal circuit voltage is greater than 4.93 V.
Possible failure modes:
1. Faulty fuel temperature sensor B-9002 wiring, short to a voltage source.
2. Faulty fuel temperature sensor B-9002 wiring, open circuit.
3. Faulty fuel temperature sensor B-9002, 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 fuel temperature sensor B-9002 for an internal failure.
Disconnect the engine harness (EN) from the fuel temperature sensor B-9002 at connector X-9005.
Use a multimeter to measure the resistance of the fuel temperature sensor B-9002 on the sensor pins :
From
X-9005 pin 1
NOTE: The fuel temperature sensor B-9002 is a Negative Temperature Coefficient (NTC) thermistor. The thermis-
tor's conductivity increases with increasing temperature and resistance decreases with increasing temperature.
A. If there is a nominal resistance value, e.g. greater than 100 Ω, leave connector X-9005 disconnected and
continue to Step 3.
B. If there is not a nominal resistance value, e.g. 0 Ω, the fuel temperature sensor B-9002 has failed. Replace
the fuel temperature sensor B-9002.
3. Check the fuel temperature sensor B-9002 wiring for a short to battery.
With the key in the OFF position, use the a multimeter to perform the following voltage check on the engine harness
(EN) side :
From
X-9005 pin 1
With the key in the ON position, use the a multimeter to perform the following voltage check on the engine harness
(EN) side :
Electrical systems - FAULT CODES
To
X-9005 pin 2
To
Chassis ground
47866583_ 02/12/2015
55.12 [55.DTC] / 26
Value
At approximately 20.0 °C (68.0 °F),
there should be between 2351 -
2648 Ω.
Value
There should be no voltage.