New Holland WorkMaster 50 Service Manual page 986

DTC 605-03-Lambda sensor O2 value above maximum threshold
Control Module : ECU
NOTE: If the Lambda sensor B-9123 is replaced, it is necessary to perform the Replacement of the Lambda Sensor
- Reset ECU Data with the Electronic Service Tool (EST) before you return the machine to service. See Lambda
sensor - Configure - Reset ECU data (Lambda sensor) (55.989), if necessary.
Context:
The Engine Control Unit (ECU) A-9000 has detected a fault associated with the oxygen sensor. This fault is a result of
an open circuit condition in the factory installed trim resistor circuit. For information regarding the functional operation
of the Lambda sensor B-9123 see Lambda sensor - Overview (55.989). For more information regarding the technical
specifications of the lambda sensor B-9123, see Lambda sensor - Technical Data (55.989).
Cause:
The ECU A-9000 is sensing an open circuit condition in the Lambda sensor B-9123 trim resistor circuit.
Possible failure modes:
1. Faulty Lambda sensor B-9123 circuit wiring, open circuit.
2. Faulty Lambda sensor B-9123, failed internally.
3. Faulty ECU A-9000, software.
Solution:
1. Verify that the fault 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 4.
2. Check the Lambda sensor B-9123 trim resistor circuit wiring for an open or short circuit condition.
Disconnect the vehicle harness (VE) from the Lambda sensor B-9123 at connector X-9123
Carefully disconnect the vehicle harness (VE) from the ECU A-9000 at connector X-9102.
With the key in the OFF position, use a multimeter to check for continuity on the vehicle harness (VE) side :
From
X-9123 pin 5
X-9102 pin K86
A. If there is no continuity, there is an open circuit condition in the Lambda sensor B-9123 trim resistor circuit wiring
in the vehicle harness (VE). Use the appropriate vehicle service manual, if necessary, to locate and repair the
broken conductor.
B. If there is continuity, continue with Step 3.
3. Replace the Lambda sensor B-9123.
Use EST to check to see that this fault has been resolved.
A. If the fault has been resolved, return the machine to service.
B. If this fault has not been resolved, check the ECU A-9000 for the appropriate software and re-flash, if necessary.
4. Visually inspect the relevant harnesses and connectors for damage, bent or dislocated pins, corroded terminals,
or broken wires.
Electrical systems - FAULT CODES
To
X-9102 pin K86
All other pins on connector X-9102
47866583_ 02/12/2015
55.12 [55.DTC] / 265
Value
There should be continuity.
There should be no continuity.