## What is Komatsu PC160LC-7 Fault Code E113?

**Fault Code E113 on the Komatsu PC160LC-7 indicates a malfunction in the engine coolant temperature sensor circuit or an abnormal coolant temperature reading detected by the Engine Control Module (ECM).** This code triggers when the ECM detects voltage readings outside the normal operating range (typically 0.5-4.5V) from the coolant temperature sensor, or when actual coolant temperature exceeds safe operating limits (usually above 105-110°C).

This fault is critical because the **ECM** relies on accurate coolant temperature data to manage fuel injection timing, engine speed, and fan engagement. On the PC160LC-7 equipped with the Komatsu SAA4D102E-2 engine, incorrect temperature readings can lead to improper combustion, reduced power output, and potential engine damage. For used excavators, this sensor circuit is particularly vulnerable to connector corrosion and wiring degradation from years of exposure to vibration and heat cycles.

## Common Symptoms

- **Engine warning light** illuminated on the instrument cluster with possible alarm beeping
- **Reduced engine power** or automatic derate mode engaging to protect the engine
- **Cooling fan** running continuously at high speed regardless of actual engine temperature
- **Difficulty starting** when the engine is cold, or rough idle conditions
- **Abnormal temperature gauge readings** showing excessively high or low coolant temperatures that don't match actual conditions

## Potential Causes

The most common technical failures triggering E113 on used PC160LC-7 excavators include:

- **Failed coolant temperature sensor** (typical lifespan 5,000-8,000 hours) showing internal resistance drift or complete open/short circuit
- **Damaged wiring harness** between the sensor and ECM, particularly at known rub points near the engine mounting brackets and behind the fuel filter assembly
- **Corroded or loose connector terminals** at the sensor plug (2-pin connector) or ECM connections, especially on machines operated in wet or coastal environments
- **Low coolant level** causing sensor exposure and erratic readings during machine operation on slopes
- **ECM internal fault** affecting the temperature input circuit (less common but possible on high-hour machines)
- **Aftermarket sensor installation** with incorrect resistance specifications for Komatsu systems

## How to Troubleshoot and Fix Code E113

**Step 1: Visual Inspection and Initial Checks**
Verify actual coolant level in the radiator and recovery tank before electrical diagnosis. Inspect the **coolant temperature sensor** (located on the thermostat housing on the left side of the engine block) for physical damage, coolant leaks, or loose mounting. Check the **2-pin connector** for corrosion, bent pins, or moisture intrusion—a common issue on used excavators. Clean connector terminals with electrical contact cleaner and dielectric grease.

**Step 2: Sensor Resistance Testing**
Disconnect the sensor connector and measure resistance across the sensor terminals using a **digital multimeter**. At 20°C (68°F), resistance should read approximately **2,400-2,700 ohms**; at 80°C (176°F), approximately **300-330 ohms**. Compare readings against Komatsu specifications in the service manual. If readings are outside specifications or show infinite resistance (open circuit) or near-zero (short circuit), replace the sensor with a genuine Komatsu part (P/N 7861-92-3320 or equivalent).

**Step 3: Wiring Harness Verification**
With the sensor disconnected, check for **continuity** between the ECM connector (typically pins C-26 and C-27 on the PC160LC-7) and the sensor connector using a wiring diagram. Resistance should be less than 1 ohm. Check for **short circuits to ground** by measuring resistance between each wire and chassis ground—readings should show infinite resistance. Inspect the harness routing for wear points, especially where it passes near exhaust components or moving engine mounts common on machines with 5,000+ hours.

**Step 4: ECM Voltage Supply Check**
Reconnect the sensor and backprobe the connector using a **multimeter** with the ignition in the ON position (engine not running). You should measure approximately **5 volts** on the signal wire (typically the darker wire). If voltage is absent or incorrect, verify ECM power supply and ground circuits before suspecting ECM failure. For used excavators, check all ECM grounds for corrosion—poor grounding causes 30% of false sensor codes.

**Step 5: Advanced Diagnostics**
Use **Komatsu KOMTRAX** or compatible diagnostic software (Komatsu Diagnostic Master or equivalent) to monitor live coolant temperature data while operating the engine. Compare sensor readings with actual temperature measured using an infrared thermometer at the thermostat housing. Variance greater than 10°C indicates sensor replacement needed. Clear codes after repairs and perform a complete operational test cycle.

---

**Disclaimer:** This guide provides general troubleshooting information for the Komatsu PC160LC-7. Always consult the official Komatsu service manual for your specific machine serial number, and consider professional diagnostic assistance for complex electrical issues. Improper repairs may void warranties or cause additional damage to used equipment.