Caterpillar Cat ET Error Code CID 508 FMI 9

Caterpillar Generator Moderate Pressure

Model: Cat ET / EMCP 4.x | Code: 508-9

Applicable Systems
EMCP 4.2

Symptoms

CID 508 (Pilot Pressure): Abnormal update rate. The Caterpillar Electronic Technician (Cat ET) displays this fault. Machine operation may be derated or shut down depending on severity.

Possible Causes

  • Sensor or actuator for Pilot Pressure failed or out of range
  • Wiring harness for CID 508 circuit open, shorted, or corroded
  • ECM parameter for Pilot Pressure out of calibration
  • Mechanical or hydraulic issue affecting the component

Troubleshooting Steps

  1. Step 1: Connect Cat ET and read active fault codes for CID 508
    Fault code 508-9 displayed with timestamp and component data
  2. Step 2: Inspect wiring harness and connector for CID 508 (Pilot Pressure)
    Wiring intact, connector clean and seated
  3. Step 3: Test Pilot Pressure sensor or actuator output
    Output within Caterpillar specification range
  4. Step 4: Check ECM for stored parameters and calibrate if needed
    Parameters within factory specification
  5. Step 5: Clear fault with Cat ET and verify no re-occurrence
    Fault cleared and does not return after test cycle

How to Reset

To reset: 1) Correct the underlying fault for CID 508. 2) Press FAULT RESET on the EMCP panel or clear via Cat ET. 3) Verify machine returns to normal operation. Caution: Do not reset without repairing the fault as the machine may operate in derated mode.

Frequently Asked Questions

  • Q: What does CID 508 mean on Caterpillar equipment?

    CID 508 refers to Pilot Pressure. It is a standard Caterpillar Component Identifier used in diagnostic systems.

  • Q: What does FMI 9 mean?

    FMI 9 indicates: Abnormal update rate. FMI (Failure Mode Identifier) describes the type of failure detected.

Comments (0)

Share your experience to help others facing the same problem.

No comments yet. Be the first to share your experience!

Leave a Comment

Source: Caterpillar SAE J1939 CID/FMI Reference, wholefleet.ca/motorsymphdiesel.com

Category: Generator