ONAN Genset Fault Code 46

[VectraDon]

The ONAN 7500 Quiet Diesel generator in my 2004 Vectra is displaying a fault code 46. It runs for less than a minute then stops. I've seen posts about this from years ago, but nothing recently. Has anyone had and solved this problem? Thanks.

[Wayne Pryor]

If I remember correctly fault code 46 is low voltage. Check all the battery terminals and voltage and the battery cable attach point on the back side of the gen. Not at shop so I'm guessing on fault code. If you don't get some kind of solution here email me at service@rickbakersrvcenter.com and I'll dig into the books.

[Dave78Chief]

From service manual 981-0522B:

INVERTER POWER SUPPLY FAULT—CODE NO. 46*
(Low battery voltage or power supply device failure)
Corrective Action:
1. Avoid running the genset while cranking the vehicle engine in installations where the genset batteries
are used to supplement the vehicle engine batteries.
2. Clean and tighten the positive (+) and negative (–) battery cable connections at the battery, vehicle
frame and genset.
3. Recharge or replace the battery. Refer to the battery manufacturer’s recommendations.
4. Install or service a battery charging system in the vehicle if the genset is not so equipped.

5. Replace the controller assembly (p. 10-2).

From what I see in the manual, beginning with Spec F (or controllers that have been replaced), Fault Code 46 replaced Fault Code 39 (Low Battery Voltage). What it is saying, is the controller thinks 12VDC battery voltage is low. Loose or corroded connections in either the positive or negative battery cable connections could cause this. The unit may or may not have a 10 amp battery charger with it. If installed, the charger could also be defective. Otherwise, the generator depends on the installed inverter/charger or converter/charger for battery charging.

Dave

[VectraDon]

In the end, the Cummins/Onan shop determined that the inverter (in the generator) was bad. $1400 and off I go.

ps. I had also previously installed three new house batteries. Great way to end the year.