CAT Data Link (CDL) - Abnormal Update Rate (Data Link)
The CAT-CID248-FMI9 (Caterpillar) diesel fault code means: CAT Data Link (CDL) - Abnormal Update Rate (Data Link). This is a moderate severity code.
Unverified. We could not confirm this code's definition against freely available manufacturer documentation, so treat the meaning, severity and fix guidance on this page as unconfirmed. Check it against the manufacturer's service information for your exact model and serial range before acting on it. This page is kept out of search engines for that reason, and we are working through this family manual by manual.
- Keep driving?
- Short distances only
- DIY difficulty
- intermediate
- Estimated cost
- $300-$1500
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View pilot availability →What Are the Symptoms of CAT-CID248-FMI9?
- Scan tool communication dropouts
- Dash cluster freezes or flickers
- Lost communication with other modules
What Causes CAT-CID248-FMI9? (Most Likely First)
- Broken J1939 twisted pair or terminating resistor missing Very Likely
- Shorted bus wire on CAN_H or CAN_L Likely
- Failed module pulling the bus down Possible
Can I Still Drive with CAT-CID248-FMI9?
Short distances only. CAT-CID248-FMI9 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does CAT code CID248-FMI9 mean?
CAT code CID248-FMI9 (CAT Data Link (CDL) - Abnormal Update Rate (Data Link)) is a moderate-severity fault on Caterpillar on-highway diesel engines. CID 248 is the CAT Data Link (CDL), measuring proprietary CAT service tool data link. FMI 9 (Abnormal Update Rate (Data Link)) indicates the specific fault mode. Use CAT ET to confirm before replacing parts. Diagnose with CAT ET (Electronic Technician) software.
Can I drive my truck with CAT code CID248-FMI9?
Short distances may be acceptable, but running long with this fault risks progressive damage or forced derate. Address promptly.
How much does it cost to fix CAT CID248-FMI9?
Typical repair is $300-$1500. Sensor / wiring fixes fall at the low end; injector, HEUI pump, turbo, or aftertreatment work falls at the high end. CAT dealer labor often requires CAT ET for calibration and parameter programming.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose CAT-CID248-FMI9?
Measure J1939 bus resistance at the diagnostic connector with key off; expect about 60 ohms.
If resistance is wrong, locate both terminators and verify integrity.
Disconnect modules one at a time while monitoring CAT ET to find a module pulling the bus down.
Inspect the twisted pair for chafing, pinches, and moisture at splice packs.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
Which Vehicles Commonly Get CAT-CID248-FMI9?
- Freightliner Classic XL with CAT C15
- Peterbilt 335 with CAT C7
- Peterbilt 386 with CAT C15
- Kenworth T800 with CAT C15
- Western Star 5900 with CAT C15
- Peterbilt 389 with CAT C15
- Peterbilt 387 with CAT C15
- Kenworth T470 with CAT C9
- Kenworth T800 with CAT C13
- Peterbilt 386 with CAT C13
- Thomas / Bluebird school bus with CAT C7
- Peterbilt 387 with CAT C13
- Peterbilt 340 with CAT C9
- Peterbilt 379 with CAT C15
- Kenworth T370 with CAT C7
- Kenworth T660 with CAT C13
- International 9400i with CAT C15
- Kenworth W900 with CAT C15
- Freightliner Columbia with CAT C13
- International 9200i with CAT C13
- International 4300 with CAT C7
- Western Star 4900 with CAT C15
- Freightliner M2 106 with CAT C7
- IC Bus shuttle with CAT C7
- International 9200i with CAT C15
- Kenworth T2000 with CAT C15
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