What are the common causes of the P0118 code on a Infiniti?

cause_ect_sensor, cause_wiring_damage, cause_connector_corrosion

How much does it cost to fix the P0118 code?

The estimated repair cost for the P0118 code is $50 - $250. This includes parts and labor.

P0118Infiniti Q50Yıllar: 1996 - 2026

Engine Coolant Temperature (ECT) Circuit High Input

ASE Sertifikalı Teknisyen Tarafından İncelenmiştir

Araç Sürülür Mü?Driving with P0118 is generally possible but not advisable for extended periods. The PCM will operate in a 'fail-safe' mode, assuming an extremely cold engine. This leads to an excessively rich fuel mixture, causing poor fuel economy, increased emissions, rough idling, and potentially spark plug fouling. More critically, the PCM may not activate the cooling fans correctly, which could lead to actual engine overheating if the engine gets hot, as it's not receiving accurate temperature data.

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Bu ne anlama geliyor?

Code P0118 indicates the ECT sensor voltage is higher than expected, suggesting the sensor reports excessively low temperature.

Yasal Uyarı: Bu arıza kodu standart OBD2 sisteminin bir parçasıdır ve 1996-2026 yılları arasında üretilen Infiniti Q50 modelleri için geçerli olabilir. Ancak bu spesifik kodun varlığı, aracınızın tam motor konfigürasyonuna ve üretim yılına bağlıdır.

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Yaygın Nedenler

Arızalı Motor Soğutma Suyu Sıcaklığı (ECT) sensörü

Hasarlı, aşınmış veya kopuk kablo tesisatı

Korozyona uğramış veya gevşek elektrik konnektörü

Dikkat Edilmesi Gereken Belirtiler

Motor Arıza Lambası yanar
Yakıt tüketiminde artış
Motoru çalıştırmada zorluk
Motor soğukken stop eder

Nasıl Teşhis Edilir

Thorough Visual Inspection of the ECT Sensor and Wiring Harness: Begin by locating the Engine Coolant Temperature (ECT) sensor, typically found near the thermostat housing or directly in the cylinder head/intake manifold. Carefully inspect the sensor's electrical connector for any signs of corrosion, bent pins, loose connections, or physical damage. Trace the wiring harness leading from the sensor for at least 12-18 inches, looking for chafing, cuts, rodent damage, or signs of previous repairs that may have failed. Ensure the sensor itself is securely threaded into its port and not leaking coolant.

Verify ECT Sensor Reading with a Professional Scan Tool: Connect an OBD-II scan tool capable of displaying live data. With the key ON, engine OFF (KOEO), observe the reported Engine Coolant Temperature. If the P0118 code is active, the scan tool will almost certainly display an extremely low temperature, often -40°F or -40°C, regardless of the actual engine temperature. Start the engine and monitor the reading; if it remains at this extremely low value, it confirms the PCM is receiving a high voltage signal, indicating an an open circuit or a sensor reporting maximum resistance.

Perform Electrical Circuit Testing at the ECT Sensor Connector: Disconnect the ECT sensor. With the key ON, engine OFF (KOEO), use a digital multimeter (DMM) to measure the voltage between the 5-volt reference wire (typically one of the two wires, consult a wiring diagram for your specific vehicle) and a known good chassis ground. You should read approximately 5.0 volts. Next, measure the resistance (ohms) between the ground wire at the sensor connector and a known good chassis ground. You should see very low resistance, ideally less than 0.5 ohms, indicating a good ground connection. If both the 5V reference and ground are present and correct at the connector, the issue is likely the sensor itself or an open circuit in the signal return wire.

Test the ECT Sensor's Internal Resistance: If the wiring and connector appear sound and the 5V reference/ground are confirmed, remove the ECT sensor from the engine. Using a DMM set to ohms, measure the sensor's resistance across its two terminals. Compare this reading to the manufacturer's specifications for the ambient temperature. To further test, you can place the sensor in a cup of hot water (with a thermometer) and observe if the resistance decreases significantly as the temperature rises. An open circuit (infinite resistance) or resistance values far outside specifications at various temperatures indicate a faulty sensor.

Check for Open Circuit in Signal Wire from Sensor to PCM: If the sensor tests good and the 5V reference and ground are present at the connector, the problem lies in the signal wire between the ECT sensor connector and the Powertrain Control Module (PCM). Disconnect both the ECT sensor and the PCM connector. Using your DMM, perform a continuity test on the signal wire from the sensor connector pin to its corresponding pin at the PCM connector. An open circuit (infinite resistance) indicates a break in the wire that needs to be located and repaired. Also, check this wire for any shorts to voltage or ground.

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Replace the Engine Coolant Temperature (ECT) Sensor: This is by far the most frequent solution for P0118. If the sensor's internal resistance is out of specification or shows an open circuit, replacing it with a high-quality OEM or equivalent aftermarket part will resolve the issue.

Repair or Replace Damaged Wiring and/or Connector: If the visual inspection or electrical tests reveal corroded, frayed, or broken wires, or a damaged electrical connector at the ECT sensor, the affected section of the harness or the connector itself must be repaired or replaced. Use proper soldering and heat-shrink techniques for durable repairs.

Repair an Open Circuit in the Signal Wire to the PCM: If diagnostic steps confirm an open circuit in the signal wire between the ECT sensor connector and the PCM, the break must be located and properly repaired. This often involves tracing the harness carefully, as damage can be hidden.

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Tahmini Tamir Maliyeti

$50 - $250

Parça$25 - $120

İşçilik$80 - $400

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Kolay

Diğer Popüler Infiniti Kodları

P0100 P0105 P0111

Engine Coolant Temperature (ECT) Circuit High Input

ASE Sertifikalı Teknisyen Tarafından İncelenmiştir

Bu ne anlama geliyor?

Code P0118 indicates the ECT sensor voltage is higher than expected, suggesting the sensor reports excessively low temperature.

Nasıl Teşhis Edilir

Sık Görülen Çözümler

Bu ne anlama geliyor?

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Dikkat Edilmesi Gereken Belirtiler

Nasıl Teşhis Edilir

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Diğer Popüler Infiniti Kodları

Scanning Engine...

Bu ne anlama geliyor?

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Diğer Popüler Infiniti Kodları