What is Caterpillar Fault Code EID1117?

Caterpillar Fault Code EID1117 indicates an Implement Pump Solenoid Control Circuit malfunction, specifically detecting an open circuit or short-to-ground condition in the hydraulic pump control system. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) detects an abnormal electrical signal from the implement pump's proportional solenoid valve circuit, which regulates hydraulic flow to attachments.

This code is critical for Caterpillar excavators because the implement pump directly controls auxiliary hydraulic functions—including bucket, thumb, and breaker operations. When EID1117 is active, the ECM may limit hydraulic performance or enter a derate mode to prevent damage to the hydraulic system. For used excavators, this fault often stems from age-related wiring degradation rather than actual solenoid failure.

Common Symptoms

• Amber warning light illuminated on the instrument cluster with reduced hydraulic power to attachments
• Loss of implement hydraulic functions or erratic attachment response (jerky bucket movements, inconsistent breaker operation)
• Hydraulic system derate where auxiliary circuits operate at reduced pressure or flow
• Intermittent fault activation, especially during machine vibration or when operating in extreme temperatures
• ECM logging multiple instances of the code, visible through Cat Electronic Technician (ET) software

Potential Causes

The most common technical causes for EID1117 in used Caterpillar excavators include:

• Damaged wiring harness near the implement pump mounting area, where cable abrasion against the frame or pump housing creates shorts or opens
• Corroded or loose connector pins at the pump solenoid interface, particularly on machines with high hour counts or exposure to moisture
• Failed proportional solenoid valve within the implement pump assembly due to internal coil degradation
• Chafed wires at known rub points along the main chassis harness, especially near articulation points
• ECM internal driver circuit failure (less common but possible in high-hour machines)
• Voltage supply issues from corroded ground connections or damaged power distribution harness

How to Troubleshoot and Fix Code EID1117

Step 1: Visual Harness Inspection Begin by thoroughly inspecting the wiring harness from the ECM to the implement pump solenoid. On used excavators, focus on areas where the harness routes near moving components or sharp edges. Look for abraded insulation, pinched wires, or heat damage. Check all connector pins for corrosion, bent terminals, or moisture intrusion—clean with electrical contact cleaner if necessary.

Step 2: Electrical Testing with Multimeter Disconnect the implement pump solenoid connector. Using a digital multimeter, measure resistance across the solenoid coil terminals (typically 3-8 ohms for most Cat proportional solenoids—verify in service manual). Then check for continuity to ground on each wire; any reading below infinite resistance indicates a short. Measure supply voltage at the connector with ignition on (should read battery voltage, typically 12-14V).

Step 3: Solenoid and ECM Verification If wiring tests pass, perform a solenoid swap test with a known-good unit or measure the solenoid's PWM signal using Cat ET diagnostic software while commanding pump operation. Check ECM connector pins for corrosion or backing-out issues. On high-hour used machines, inspect the chassis ground strap connections, as poor grounds frequently cause false circuit faults.

Step 4: Software Diagnostics Connect Cat Electronic Technician (ET) to perform active tests of the implement pump circuit. Monitor real-time solenoid command versus actual response. Clear codes after repairs and cycle the system through full range to verify fix.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Caterpillar service manual for your specific model and serial number. If unfamiliar with electrical diagnostics or hydraulic systems, seek assistance from a certified Cat technician to prevent equipment damage or safety hazards.