DPF Soot Load Above Normal
The CAT-CID1835-FMI0 (Caterpillar) diesel fault code means: DPF Soot Load Above Normal. This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- advanced
- Estimated cost
- $400-$3500
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Common Symptoms
- DPF warning lamp or HEST lamp
- Forced regen required
- Engine derate if regen not completed
- Black smoke or poor fuel economy
- Check Engine Light
Probable Causes (Ranked by Likelihood)
- Excessive short-trip / idle operation preventing passive regen Very Likely
- Failing or missed active regens Likely
- DPF partially plugged with ash (requires cleaning/bake service) Likely
- Faulty differential pressure sensor or sample lines plugged Likely
- HC doser / aftertreatment injector not firing properly Possible
- EGT sensors reading wrong, preventing regen authorization Possible
Step-by-Step Diagnostic Procedure
Connect CAT ET and read DPF soot load, ash load, and regen history.
Inspect dP sensor and sample lines for soot blockage.
Verify DPF inlet and outlet EGT sensors read matching at cold start.
Command a stationary regen via CAT ET and monitor EGTs climbing as expected (target ~1100°F at DPF inlet).
If stationary regen fails or ash load is high, DPF requires off-truck cleaning / bake service.
Check HC doser / 7th injector operation for active regen events.
Frequently Asked Questions
What does CAT CID1835-FMI0 mean?
CAT code CID1835-FMI0 (DPF Soot Load Above Normal) is a serious-severity aftertreatment fault on 2007-2010 C13/C15 ACERT engines. DPF soot loading too high. Regen may be disabled or failing.
How do I fix DPF issues on my CAT ACERT engine?
Run a CAT ET-commanded stationary regen first. If it fails or the DPF is ash-loaded (>100g typical), send the DPF out for cleaning/bake at a specialized shop. Verify EGT sensors, dP sensor, and the 7th/HC injector dose properly as part of diagnosis.
How much does it cost to fix CAT CID1835-FMI0?
DPF cleaning/bake service is $400-$800. Sensor replacement is $200-$600 installed. HC doser / 7th injector replacement is $800-$1500. A failed DPF substrate replacement is $2500-$3500 at a dealer.
Sources
This page is built from documented references. Verify against your own service info before repair work.