New Holland WorkMaster 50 Service Manual page 733

DTC 131-03-Engine coolant temperature sensor voltage is higher
than expected
Control Module : ECU
Context:
The Engine Control Unit (ECU) A-9000 monitors the engine coolant temperature sensor B-9003 signal circuit. If the
ECU A-9000 determines that voltage is higher than expected in the engine coolant temperature sensor B-9003 signal
circuit, this fault will occur. If this fault is active, the ECU A-9000 will set the engine coolant temperature value to a
fixed replacement value of 89.96 °C (193.93 °F).
Cause:
The engine coolant temperature sensor B-9003 signal voltage is greater than 4.93 V.
Possible failure modes:
1. Faulty engine coolant temperature sensor B-9003, short to a voltage source.
2. Faulty engine coolant temperature sensor B-9003, 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 6.
2. Check the coolant temperature sensor B-9003 wiring for a short circuit.
Disconnect the engine harness (EN) from the coolant temperature sensor B-9003 at connector X-9006.
With the key in the OFF position, use a multimeter to perform the following voltage check on the engine harness
side:
From
X-9006 pin 1
With the key in the ON position, use a multimeter to perform the following voltage check on the engine harness
side:
From
X-9006 pin 1
A. If the specified values are not measured, there is a short to a voltage source in the coolant temperature sensor
B-9003 wiring. Use the appropriate service manual, if necessary, to locate and repair the shorted conductor.
B. If the specified values are not measured, leave connector X-9006 disconnected and continue to Step 3.
3. Check the coolant temperature sensor B-9003 engine harness (EN) wiring for a short circuit.
Disconnect the engine harness (EN) from the ECU A-9000 at connector X-9001.
With the key in the OFF position, use a multimeter to perform the following continuity check on the engine harness
(EN) side:
Electrical systems - FAULT CODES
To
Chassis ground
To
Chassis ground
47866583_ 02/12/2015
55.12 [55.DTC] / 12
Value
There should be no voltage.
Value
There should be less than 5.5 V