Caterpillar CID 87 FMI 4 - Cylinder Cutout #4: Voltage Below Normal, or Shorted to Low Source

Caterpillar Heavy Equipment Major Fuel Injector

Model: CAT Electronic Control Module | Code: CID-87-FMI-4

Applicable Systems
EMCP 4.2

Symptoms

The Caterpillar Electronic Technician (ET) displays CID 87 with FMI 4: Cylinder Cutout #4 - Voltage Below Normal, or Shorted to Low Source . The specific symptoms depend on the component and severity level. The engine or machine may exhibit reduced performance, warning indicators, or protective shutdown.

Possible Causes

  • Cylinder Cutout #4 sensor or actuator fault - Voltage Below Normal, or Shorted to Low Source
  • Wiring harness damage, corrosion, or loose connections
  • Connector pin corrosion or terminal damage
  • ECM internal circuit or processor fault
  • Component mechanical failure related to Cylinder Cutout #4

Troubleshooting Steps

  1. Step 1: Connect Caterpillar ET and retrieve active diagnostic codes for CID 87 FMI 4
    Diagnostic code details and freeze frame data retrieved
  2. Step 2: Inspect the wiring harness and connectors for the affected component
    No visible damage, chafing, or corrosion found
  3. Step 3: Check sensor/actuator power supply, ground, and signal circuits with a multimeter
    Values match CAT specifications or discrepancies identified
  4. Step 4: Perform component-specific tests per CAT service manual procedures
    Component passes or fails definitive test
  5. Step 5: Clear diagnostic codes and operate machine through normal cycle to verify repair
    Code does not return and system operates normally

How to Reset

To reset Caterpillar CID 87 FMI 4: 1) Repair the underlying fault per troubleshooting steps. 2) Use Caterpillar ET to clear the diagnostic code. 3) Cycle the ignition key off for 30 seconds, then on. 4) Operate the machine through normal conditions. 5) If the code returns, contact an authorized CAT dealer for further diagnosis.

Frequently Asked Questions

  • Q: What does Caterpillar CID 87 FMI 4 mean?

    CID 87 FMI 4 indicates: Cylinder Cutout #4 - Voltage Below Normal, or Shorted to Low Source . This is a Caterpillar diagnostic code related to Fuel Injector.

  • Q: How do I clear Caterpillar CID 87 FMI 4?

    Fix the root cause, then use Caterpillar ET to clear the code. If persistent, contact a CAT dealer.

  • Q: Is Caterpillar CID 87 FMI 4 critical?

    Severity: Major. Reduce operations and service promptly.

Related Caterpillar Fault Codes

Source: Caterpillar Electronic Technician (ET) / CID-FMI Reference Guide

Category: Heavy Equipment