RDC2
Lo Crank Vlt
Low cranking voltage
Electrical · Warning
Warning on the residential RDC2 table. TP-7092 says battery voltage dropped below 3.5 VDC during engine cranking. The check is to charge or replace the battery. This 3.5 volt figure is the residential manual's number. Kohler's liquid-cooled TP-6905 describes low cranking voltage differently, so that threshold is not mixed in here. OnCue Plus calls the related warning Low Cranking Voltage.
Seen on: 14RCA, 14RCAL, 20RCA, 20RCAL, 26RCA, and 26RCAL sets with the RDC2 controller (TP-7092).
Likely causes
- A battery that collapses under starter load.
- Connections that drop the voltage the controller measures while cranking.
Checks an owner can do
- Have the battery tested and replace it if it will not hold a charge. Follow the battery maker's charging steps.
- Clean and tighten the cable ends with the generator off.
When to call a pro
If a known-good battery still falls through 3.5 volts while cranking, the cables, starter draw, or charger need a dealer.
Source
Wording follows that document. Firmware can change a threshold. If this page and the manual shipped with your unit disagree, follow the manual.
What fixed mine
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Related Kohler codes
https://generatorcodes.com/brand/kohler/lo-crank-vlt