What is Doosan Excavator Fault Code E001136-02?

Fault Code E001136-02 indicates a malfunction in the Engine Oil Pressure Sensor Circuit - abnormal voltage detected. This diagnostic trouble code (DTC) is triggered when the Electronic Control Module (ECM) receives a voltage signal from the engine oil pressure sensor that falls outside the manufacturer's predetermined acceptable range (typically 0.5-4.5V for standard pressure transducers).

This code specifically points to an electrical circuit issue rather than actual low oil pressure, though both conditions can coexist. The engine oil pressure sensor is critical for monitoring lubrication system performance on Doosan excavators. When this sensor circuit fails, the ECM cannot accurately determine if adequate oil pressure exists to protect engine bearings, camshafts, and turbocharger components from catastrophic wear. In used excavators, this code often appears due to connector corrosion or harness deterioration rather than sensor failure itself.

Common Symptoms

When Code E001136-02 is active, operators typically experience:

• Engine warning lamp illuminated on the instrument cluster (amber or red depending on severity)
• Engine derate mode engaged, limiting RPM to 1500-1800 to prevent potential damage
• Audible warning alarm sounding intermittently or continuously from the cab
• Erratic oil pressure gauge readings on the dashboard, fluctuating between normal and zero
• Engine may enter limp mode or refuse to start on some Doosan models with strict protection protocols

Potential Causes

The most common technical causes for E001136-02 in used Doosan excavators include:

• Damaged or corroded wiring harness at the sensor connector (common failure point where harness rubs against engine block)
• Failed engine oil pressure sensor due to internal circuit board degradation or diaphragm failure
• Corroded connector pins at the sensor or ECM connection points from moisture intrusion
• Chafed sensor wiring near mounting brackets or cable ties that have worn through insulation
• ECM internal circuit failure (rare, but possible in high-hour machines)
• Poor ground connection at the sensor mounting point or ECM ground strap
• Contaminated engine oil causing sensor membrane fouling and electrical resistance changes

How to Troubleshoot and Fix Code E001136-02

Step 1: Visual Inspection Begin by inspecting the engine oil pressure sensor (typically located near the oil filter housing on Doosan engines). Check for physical damage, oil contamination on the connector, or corrosion on connector pins. On used excavators, carefully trace the sensor harness back to the ECM, looking for wear points where the harness contacts frame members or vibrates against metal surfaces.

Step 2: Electrical Testing Using a digital multimeter (DMM), disconnect the sensor and measure resistance across the sensor terminals (typical range: 50-250 ohms depending on model). Then check supply voltage at the harness connector with ignition ON - you should see approximately 5V reference voltage from the ECM. Measure ground continuity between the sensor ground pin and battery negative (should be less than 1 ohm resistance).

Step 3: Signal Testing With the sensor reconnected and engine running, backprobe the signal wire using your multimeter set to DC voltage. Normal operating pressure should show 1.5-3.5V depending on RPM. If voltage reads 0V or 5V constantly, the sensor has failed. If readings fluctuate erratically, suspect intermittent wiring faults or connector issues.

Step 4: Repair or Replace For used excavators, replace corroded connectors using OEM-quality weatherproof connectors and apply dielectric grease to prevent future corrosion. If the sensor tests faulty, install a genuine Doosan oil pressure sensor (aftermarket sensors often cause repeat codes). Repair any chafed wiring with proper heat-shrink tubing and secure harnesses away from moving components. Clear codes using Doosan diagnostic software (DMS-5) or compatible scan tool and verify repair with a test run.

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Disclaimer: This guide provides general troubleshooting information. Always consult the official Doosan service manual for your specific excavator model and serial number. If unfamiliar with electrical diagnostics or working around pressurized engine systems, seek assistance from a certified heavy equipment technician.