What is Caterpillar Fault Code CID1370?

Caterpillar fault code CID1370 indicates an Implement Pump Solenoid Current Below Normal condition, meaning the Electronic Control Module (ECM) has detected lower-than-expected electrical current flowing through the hydraulic implement pump's proportional control solenoid. This Diagnostic Trouble Code (DTC) specifically monitors the electrical circuit integrity of the solenoid that regulates hydraulic flow to the implement (attachment) system on Caterpillar excavators.

This code is critical because the implement pump solenoid directly controls hydraulic pressure and flow to your bucket, thumb, or other attachments. When current levels drop below manufacturer specifications—typically due to circuit resistance or component failure—the ECM cannot properly modulate hydraulic performance, leading to reduced attachment functionality and potential operational shutdowns on machines equipped with electronic load-sensing hydraulic systems.

Common Symptoms

Operators may experience the following when CID1370 is active:

• Sluggish or unresponsive attachment movements (bucket curl, arm extension operate slowly or erratically)
• Amber or red warning lights on the instrument cluster, often accompanied by a diagnostic message
• Hydraulic implement function derate where attachment speed is limited to protect the system
• Intermittent loss of auxiliary hydraulic power, particularly during simultaneous multi-function operations
• Audible alarm in the cab with potential ECM-initiated engine power reduction on newer models

Potential Causes

The most common technical causes for CID1370 on used Caterpillar excavators include:

• Open circuit or high resistance in the solenoid harness, often from wire chafing at known rub points near the pump mounting area or along the upper structure rotation path
• Failed implement pump solenoid coil with internal winding breaks (common after 5,000+ operating hours)
• Corroded or loose connector pins at the solenoid or ECM interface, particularly on machines exposed to wet or corrosive environments
• Damaged wiring insulation from rodent activity or improper previous repairs creating intermittent ground faults
• ECM power supply issues affecting multiple circuits simultaneously (less common but possible on high-hour machines)

How to Troubleshoot and Fix Code CID1370

Step 1: Initial Visual Inspection Begin by thoroughly inspecting the implement pump solenoid connector and associated wiring harness. On used excavators, focus on areas where the harness contacts frame members or hydraulic lines. Look for abraded insulation, green corrosion on connector pins, or oil contamination that may create current leakage paths. Clean all connections with electrical contact cleaner and apply dielectric grease.

Step 2: Electrical Testing Using a digital multimeter, disconnect the solenoid connector and measure coil resistance across the solenoid terminals (should typically read 3-8 ohms depending on model—consult your service manual). Then check for continuity from each solenoid wire back to the ECM connector. Any reading above 2-3 ohms indicates excessive resistance requiring harness repair or replacement.

Step 3: Solenoid Current Testing With Caterpillar Electronic Technician (Cat ET) diagnostic software connected, perform an active solenoid test while measuring actual current draw with a clamp meter. Compare readings against specifications (usually 800-1200 mA at full command). If current remains low despite good resistance readings, the solenoid coil is likely failing internally and requires replacement.

Step 4: Harness Routing Verification For used machines with previous repairs, verify the harness follows factory routing specifications. Incorrect positioning after component replacement is a frequent cause of intermittent codes due to chafing during operation. Secure all wiring with OEM-style clips and ensure adequate clearance from moving components.

Professional Disclaimer: While these diagnostic steps assist in identifying CID1370 causes, hydraulic system repairs involve high-pressure components and complex electrical systems. Always consult Caterpillar service documentation specific to your machine's serial number, and consider professional diagnosis if you lack appropriate diagnostic tools or experience with electrohydraulic systems.