New Holland WorkMaster 50 Service Manual page 982

DTC 601-02-Lambda sensor nernst cell open circuit
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:
For information regarding the functional operation of the Lambda sensor B-9123 see Lambda sensor - Overview
(55.989). The Engine Control Unit (ECU) A-9000 has determined that the Lambda sensor B-9123 nernst signal is not
present. The Lambda sensor B-9123 is the primary measurement device for ECU A-9000 fuel control, to determine
if the engine is too rich or too lean. 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 nernst signal 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 nernst signal circuit wiring for an open circuit condition.
Disconnect the vehicle harness (VE) from the Lambda sensor B-9123 at connector X-9123.
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 perform the following continuity check for an open circuit on
the vehicle harness (VE) side :
From
X-9123 pin 6
A. If there is no continuity, there is an open circuit condition in the vehicle harness (VE) between connector X-9123
pin 6 and X-9102 pin K63.Use the appropriate vehicle service manual, if necessary, to locate and repair the
broken conductor.
B. If there is continuity, leave connector X-9123 disconnected and continue to Step 3.
3. Replace the Lambda sensor B-9123.
Use the EST, see Lambda sensor - Configure - Reset ECU data (Lambda sensor) (55.989) if necessary, to
perform the Replacement of the Lambda Sensor - Reset ECU Data.
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.
Electrical systems - FAULT CODES
To
X-9102 pin K63
47866583_ 02/12/2015
55.12 [55.DTC] / 261
Value
There should be continuity.