Cummins/Onan — Engine Control System Checkout (Engine Control Tester)
Testing & diagnosis
From a Cummins/Onan service manual — check it applies to your exact model before use.
Applies to: Cummins/Onan DFM
Before you start
- Engine will not start with controls in this configuration
Procedure
- Remove front cover of engine module rack
- Remove Cycle Cranker module A14 and insert Engine Control Tester module into A14 position
- Set rheostat on Tester module fully counterclockwise
- Place R-S-R switch in Run position, depress Lamp Test switch to test fault lamps
- Proceed through checkout items 1 through 31 using the Tester
Tools required
- Engine Control Tester module Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Cranking light ON; Tester rheostat to 2300 rpm; 65-85 seconds overcrank; 650 rpm disconnect; 10-20 seconds LOP; 400 rpm; below 30 rpm overcrank
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.