What is Komatsu PC110-8M0 Fault Code CA153?

Fault Code CA153 on the Komatsu PC110-8M0 indicates a malfunction in the Engine Control Module (ECM) communication circuit, specifically a CAN bus communication error between the engine controller and machine monitoring system. This code triggers when the Electronic Control Unit (ECU) detects an interruption, voltage irregularity, or data transmission failure on the Controller Area Network (CAN) communication line.

This fault is critical for the PC110-8M0 because the CAN bus serves as the central nervous system for machine diagnostics, coordinating communication between the engine management system, hydraulic controllers, and operator display panel. When communication breaks down, the machine cannot properly regulate engine performance, hydraulic functions, or display accurate operational data, potentially leading to reduced productivity and unsafe operating conditions.

Common Symptoms

• Warning lights illuminated on the dashboard, specifically the engine malfunction indicator or system error light
• Monitor display failures showing incomplete or frozen data for engine temperature, fuel levels, or operating hours
• Intermittent loss of throttle response or unexpected engine derating to low-idle mode
• Hydraulic function irregularities including sluggish boom/arm movements or inconsistent swing speed
• Inability to access diagnostic information through the standard operator interface panel

Potential Causes

The most common technical causes for CA153 on used PC110-8M0 excavators include:

• Corroded or loose CAN bus connectors at the ECM harness connection points, particularly the 38-pin main connector which is vulnerable to moisture intrusion on older machines
• Damaged CAN communication wiring due to harness chafing against the engine block near the fuel injection pump mounting bracket—a known wear point on this model
• Failed termination resistors (120-ohm resistors) at either end of the CAN network causing signal reflection issues
• ECM power supply problems including degraded ground connections at chassis mounting points or voltage drops from aging battery cables
• Water damage to the engine harness from deteriorated cab floor seals allowing moisture into the right-side harness routing channel

How to Troubleshoot and Fix Code CA153

Step 1: Visual Inspection and Connector Check Begin by inspecting all CAN bus harness connectors for corrosion, bent pins, or moisture. On used excavators, pay special attention to the ECM connector located behind the right-hand access panel. Disconnect and clean all terminals with electrical contact cleaner, then apply dielectric grease before reconnection.

Step 2: CAN Bus Continuity and Resistance Testing Using a digital multimeter, measure resistance between CAN-High and CAN-Low terminals at the ECM connector with all controllers connected—you should read approximately 60 ohms (two 120-ohm terminating resistors in parallel). Check for short circuits to ground on both CAN lines; readings should show infinite resistance.

Step 3: Voltage and Signal Verification With ignition on and engine off, measure CAN-High voltage (should read 2.5-3.5V) and CAN-Low voltage (should read 1.5-2.5V) at the ECM. Inspect the twisted-pair CAN wiring along the engine-to-chassis harness route for physical damage, especially where it passes near sharp metal edges.

Step 4: Harness and Ground Point Restoration For used machines, thoroughly inspect chassis ground points G101 and G103 (located on the right engine mounting frame). Remove, wire-brush clean, and re-torque to 18 ft-lbs. Check for harness chafing at the fuel pump bracket and reroute if necessary using proper protective loom and cable ties.

Disclaimer: This guide provides general troubleshooting information. Always consult the official Komatsu PC110-8M0 service manual and consider professional diagnostic assistance for complex electrical issues. Improper repairs may cause additional damage or safety hazards.