40
9 Faults/Warnings
9.3.1 Faults - Causes and Solutions
9.3.1.1 Probe voltage too low
• Probe + / - reversed probe connection terminal 33-34 change
• Probe poisoned replace
NOTICE
Probe voltage to air +5 to –30 mV
9.3.1.2 Defective LS2 Probe Heating
NOTICE
In 99 % of all cases, the LS2 Lambda Probe was disconnected during operation. Reset fault
either by the multifunction key or by the display and operating unit etc.
1. Reset fault either by the multifunction key or by the display and operating unit etc.
2. A defect only exists if the fault cannot be reset.
Possible causes:
• Check fuse F 5 (see chapter 11.4.4 LT2 Power Electronic Type 657E1882
• Check the probe heater. In an intact heater, ca.10 (9 ... 11 ) can be measured
between terminal 35 and 36. If not (R ) heater faulty. Replace probe.
• If intact, check the supply voltage: The probe heater must be supplied with about 13 VDC,
cyclically reversed. If not, check the wiring and the terminals and tighten if necessary.
NOTICE
The probe is heated with direct current at approx. 13 V, cyclically reversed. Therefore the use
of a multimeter to measure it is somewhat difficult.
NOTICE
The current heating data can be read out from LT2 operating parameters 41/42/43.
9.3.1.3 Broken Wire Probe/Defective Probe
This message is indicated if the AC internal resistance (R
i
) or the ZrO
2
cell exceeds the per-
missible limit of 300 . Before or after this message you normally will get the warning ’Inner
resistance [probe] too high’.
Possible reasons:
• The probe is disconnected (measuring signal on terminals 33 to 34)
• Loose connection check the terminals, re-tighten
• Probe too cold, possibly enhance the heating power gradually (0.5 W)
• Check wiring, if OK replace probe
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