Caterpillar Fault Codes List: All about Cat's SPN, FMI, CID, and MID codes and how to decipher them

Key advantage of using telematics like VisionLink or My.Cat.com is having immediate access to fault codes. Some fault codes don't require immediate action, but others may signal a critical safety or breakdown concern. As a fleet owner or equipment manager, you want to know about this fault code as it happens.

If you use VisionLink's website, these error codes will appear with usually clear description, like "Right Joystick Thumbwheel Position Sensor-Voltage Above Normal" or "Brake Oil Temperature Sensor (Right Rear)-Voltage Below Normal". But sometimes all you'll find is codes, like "MID 82, CID 168, FMI 4" which isn't very helpful. If you're importing VisionLink data via their API, then the AEMP 2.0 standard will contain only coded information, leaving with you with the complex task of interpreting these codes.  Here's a quick summary of how to do so.

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SPN Suspect Parameter Numbers

There are diagnostic fault codes referring to specific components or system circuits. Clue tracks over 3500 different SPN codes, used by Caterpillar equipment. Here is a sample of the codes we track. Checkout complete SPN fault codes list.

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MID Module Identifier

Newer Caterpillar machines use Caterpillar Electronic Controls, which can help pinpoint specific modules, components and failure modes. MID identifies the specific electronic control module that diagnosed the fault, like MID 116- Integrated Brake Control. Here's a sample list of Caterpillar MIDs. Checkout complete MID fault codes list.

CID Component Identifier

The CID helps pinpoint a specific circuit or system, usually within the MID. E.g. CID 854 - Brake Oil Temperature Sensor (Right Rear), is related to MID 116. Our top 3 CID fault codes at Clue are 3565 (Air Conditioner Suction Pressure Sensor), 1961 (Hydraulic Oil Temperature Sensor) and 1469 (SAE J1939 Data Link).

Read also: Komatsu Fault Codes List

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‍FMI Failure Mode Identifier

These are essentially the "message" from the circuit affected. For example, MID 116-CID 854 may report FMI 4, “Voltage below normal”. From what we can see amongst hundreds of thousands of fault code at Clue, the most common FMI codes are 3 (“Voltage above normal”) and 9 (“Abnormal update rate”). Some examples here:

The advantage of using a platform like Clue is that you won't have to worry about interpreting any of these codes. With a complete list of FMI fault codes available, your operators, mechanics, and equipment managers will receive everything in plain English. Clue does all the hard work of interpreting SPN, MID, CID, and FMI codes for you. Best of all, we do that for all OEMs, not just Caterpillar. To learn more, contact us today via support@getclue.com.