Volvo EC210B LC Fault Code 128 PID 1105: Technical Guide

What is Volvo EC210B LC Fault Code 128 PID 1105?

Fault Code 128 PID 1105 indicates an abnormal electrical condition in the intake manifold pressure sensor circuit on the Volvo EC210B LC excavator. This diagnostic trouble code (DTC) is triggered when the Engine Control Module (ECM) detects a voltage signal from PID 1105 (intake manifold absolute pressure sensor) that falls outside the expected operating range—typically indicating values too high or too low for current engine conditions.

The intake manifold pressure sensor is critical for the ECM to calculate proper fuel injection timing and volume. On the Volvo EC210B LC's D6E engine, this sensor directly impacts turbocharger performance, combustion efficiency, and emissions control. When this code becomes active, the ECM cannot accurately measure engine load, potentially causing power loss and increased fuel consumption.

Common Symptoms

• Engine warning lamp illuminated on the instrument panel with reduced power output (derate mode)
• Rough idling or hesitation during acceleration, particularly under load
• Black smoke from the exhaust indicating improper fuel-to-air ratio
• Reduced hydraulic performance due to engine not reaching optimal RPM
• Hard starting or extended cranking time, especially in cold conditions

Potential Causes

On used Volvo EC210B LC excavators, the following issues are most frequently responsible for triggering Code 128 PID 1105:

• Intake manifold pressure sensor failure due to heat cycling and age-related component degradation
• Damaged wiring harness between the sensor and ECM, particularly at known rub points near the engine firewall and along the right-hand chassis rail
• Corroded or loose electrical connectors at the sensor—common on machines with extended outdoor exposure
• Vacuum leaks in the sensing hose or manifold affecting pressure readings
• ECM internal fault or corrupted calibration data (less common but possible in high-hour machines)

How to Troubleshoot and Fix Code 128 PID 1105

Step 1: Connect Volvo VOCE (Volvo Online Communication Equipment) or compatible J1939 diagnostic software to retrieve active and pending codes. Document freeze frame data showing manifold pressure readings when the fault occurred.

Step 2: Perform a visual inspection of the intake manifold pressure sensor (located on the intake manifold, driver's side). Check for physical damage, oil contamination, or disconnected vacuum hoses. Inspect the wiring harness for abrasion, especially where it passes over the engine block and through harness retention clips.

Step 3: Using a digital multimeter, check sensor supply voltage at the connector (should be approximately 5 volts with key on, engine off). Test ground continuity to the ECM—resistance should be less than 1 ohm. Measure sensor signal voltage at idle and compare to specifications (typically 1.5-2.5V depending on altitude).

Step 4: For used excavators, thoroughly clean all connector terminals with electrical contact cleaner and apply dielectric grease. Check for harness chafing at common failure points: near the turbocharger heat shield and where the harness enters the ECM enclosure.

Step 5: If sensor output remains out of range after harness verification, replace the intake manifold pressure sensor with a genuine Volvo or OEM-equivalent part. Clear codes and perform a test cycle under load.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Volvo service manual for your specific machine serial number and consider professional diagnostic services for complex electrical issues.