Air Filter Restriction — Alert
The DOOSAN-CODE-9 (Doosan/Ingersoll-Rand SECU portables) diesel fault code means: Air Filter Restriction — Alert. This is a moderate severity code.
- DIY difficulty
- moderate
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Common Symptoms
- SECU display shows code 9 as an alert; the machine keeps running
- Possible reduced performance from a clogged air filter
Probable Causes (Ranked by Likelihood)
- Clogged engine/compressor air filter High
- Wire W009 shorted to +12V Low
Frequently Asked Questions
Does code 9 shut the machine down?
No — it is an alert, not a shutdown. The filter restriction switch (normally open, on the air filter box) has closed, which almost always means the filter is due. Replace the filter; if the code stays on, the switch wiring is shorted.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
This code set applies to SECU-display machines (7/51, 7/71, XP185, P260). Newer Tier-4-Final Doosan portables such as the P185WDOU-T4F use a DIFFERENT code set (CPR codes) — confirm which controller your machine has before acting on this page.
Replace the air filter — the factory procedure step 1; the alert should clear.
If the alert persists with a new filter, check wire W009 continuity from the restriction switch back to the SECU, and replace it if shorted to +12 VDC.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- Doosan Portable PowerElectronic Service Manual, Book 23307366 Rev A: Compressor Fault Codes (official dealer service documentation for 7/51, 7/71, XP185, P260)
Commonly Affected Vehicles
- Doosan / Ingersoll-Rand SECU-controller portable compressors: 7/51, 7/71, XP185, P260
Related Codes
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