Cummins fault code 2732

What it means

Cummins' description: Aftertreatment Fuel Drain Valve Circuit - Voltage above normal, or shorted to high source.

SPN 4097 is Aftertreatment 1 Fuel Drain Actuator. FMI 3 means the voltage on the circuit is higher than possible for a good sensor, usually an open signal wire, a short to a power wire, or a failed sensor.

The DOC (diesel oxidation catalyst) sits ahead of the DPF and burns fuel and hydrocarbons to heat the exhaust for regeneration. Some engines have a separate aftertreatment fuel doser (the 7th injector) that sprays fuel into the exhaust for regen.

What the lamp means

An amber (yellow) warning lamp means the engine can usually keep running, but the fault should be repaired soon, ideally the same day.

Common causes

FMI 3 is an electrical or signal fault, so start with the circuit:

• Temperature sensor or sensor module failed
• Aftertreatment fuel doser, shutoff valve or pressure sensor wiring fault
• Connector heat damage

If the circuit checks out, the reading may be real. Other possibilities: aftertreatment fuel injector clogged or coked up; dOC face-plugged with soot or oil; dOC catalyst worn out or contaminated.

What you can check before calling

• Look for soot or fuel residue at the aftertreatment fuel doser and lines
• Check for exhaust leaks between the turbo and the DOC
• Note whether regens are completing or being interrupted

Clearing the code without fixing the cause usually brings it right back, and on emissions systems it can restart derate timers. For the bigger picture, read our guide: DPF regeneration explained: passive, active and forced.

Engines and sources

Listed by Cummins for: QSX 15, QSG 12. Cummins uses the same fault code numbers across its electronic engines, including on-highway models like the ISB/B6.7, ISL/L9 and ISX/X15, though not every code applies to every engine or software level. Source: Cummins Tier 4 Fault Codes. Always confirm with Cummins service information (QuickServe) for your engine serial number.