P1120 – OBD-II DTC

OBD-II DTC P1120 – Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage/IAT – B Circuit High Input

DTC P1120 meaning

DTC P1120 refers to a diagnostic trouble code indicating an intermittent high voltage condition in the Engine Coolant Temperature (ECT) sensor circuit. This code can also relate to the Intake Air Temperature (IAT) sensor circuit, suggesting a high input signal. The ECT sensor is crucial for monitoring the engine’s temperature, which helps the engine control module (ECM) adjust fuel delivery and ignition timing for optimal performance.

DTC P1120 symptoms

Common symptoms associated with DTC P1120 may include:

• Check Engine Light illuminated
• Engine overheating or running too cool
• Poor fuel economy
• Rough engine idle
• Increased emissions

DTC P1120 causes

Several factors can lead to the triggering of DTC P1120, including:

• Faulty ECT sensor
• Wiring issues such as shorts or open circuits
• Corroded or loose electrical connectors
• Faulty ECM
• Issues with the IAT sensor

DTC P1120 seriousness

DTC P1120 can be serious as it may lead to engine performance issues, including overheating or inefficient fuel usage. If left unaddressed, it can cause further damage to the engine or related components. It is advisable to diagnose and repair the issue promptly to maintain vehicle reliability and performance.

How to diagnose DTC P1120

To diagnose DTC P1120, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P1120 code.
2. Inspect the ECT sensor and its wiring for any visible damage or corrosion.
3. Check the electrical connectors for tightness and cleanliness.
4. Test the ECT sensor using a multimeter to ensure it operates within specifications.
5. Examine the IAT sensor and its circuit for similar issues.
6. Check for any additional trouble codes that may provide further insight.

How to fix DTC P1120 step-by-step instructions

To fix DTC P1120, follow these steps:

1. Repair or replace any damaged wiring or connectors related to the ECT and IAT sensors.
2. If the ECT sensor is faulty, replace it with a new one.
3. Clear the DTC using an OBD-II scanner.
4. Start the engine and allow it to reach operating temperature while monitoring the ECT sensor readings.
5. Check for the reappearance of the P1120 code after a test drive.

How to erase DTC P1120

To erase DTC P1120, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the trouble codes.
5. Disconnect the scanner and start the engine to ensure the code does not return.

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