New Holland Workmaster 50, Service Manual

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Electrical systems - FAULT CODES
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 To Value
X-9006 pin 1 Chassis ground There should be no voltage.
With the key in the ON position, use a multimeter to perform the following voltage check on the engine harness
side:
From To Value
X-9006 pin 1
Chassis ground
There should be less than 5.5 V
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:
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