Cummins/Onan — Ignition Module Test
Testing & diagnosis
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Severe personal injury or death can result if engine starts while manually rotating crankshaft
Procedure
- Remove both spark plug cables from ignition coil to prevent starting.
- Connect voltmeter positive to coil negative terminal; negative to engine ground.
- Remove all leads from positive (+) coil terminal.
- Jumper ignition module red lead to battery positive (+) terminal.
- Rotate engine clockwise using socket wrench on generator through bolt.
- Replace module if voltage does not jump from about 1 volt to about 12 volts each revolution.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Approximately 1 volt to approximately 12 volts
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.