New Holland WorkMaster 50 Service Manual page 991

Electrical systems - FAULT CODES
DTC 607-04-Lambda sensor O2 calibrator too low error
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 performs an electrical zero-offset calibration every 10 min of engine operation
on the Lambda sensor B-9123 as long as the engine has been running for longer than 10 s after start, after-treatment
regeneration is not active, the engine is in operating range one (speed between 300 - 1200 RPM and load between
2.00 - 11.00 mg per stroke), and the calibration is not inhibited due to a failure. The measured oxygen signal during
calibration should be between - 0.200 - 0.200 V. If the oxygen signal, during this calibration, is out of range, less than -
0.200 V, this fault will occur. For more information regarding fuel system troubleshooting, see Fuel injection system
- Troubleshooting (10.218). 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 Lambda sensor B-9123 oxygen level signal, during calibration, to the ECU A-9000 is less than – 0.200 V.
Possible failure modes:
1. Faulty fuel back-flow, excessive.
2. Faulty Exhaust Gas Recirculation (EGR) Z-9000 valve, stuck open. (If applicable)
3. Faulty Lambda sensor B-9123, contaminated.
4. Faulty ECU A-9000, software.
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