DTC Code P1120 – What does this code mean?

<ul> <li><a href="/problems/engine-warning-light-on"><b>Engine Light ON</b></a>: The check engine light or service engine soon warning light illuminates, indicating a potential issue with the throttle position sensor.</li> <li><a href="/problems/throttle-control-error"><b>No Throttle Response</b></a>: The vehicle may experience a lack of throttle response, which can be linked to the throttle position sensor being out of range.</li> </ul>

<ul><li>The throttle position sensor may be faulty, leading to incorrect readings and triggering the error code.</li><li>An open or shorted throttle position sensor harness can disrupt the signal, causing the sensor to report out-of-range values.</li><li>Poor electrical connections in the throttle position sensor circuit can result in intermittent or inaccurate sensor data.</li><li>If the throttle position sensor is not properly adjusted, it may not align correctly with the throttle body, causing erroneous readings.</li></ul>

<ul> <li><b>Initial Inspection</b>: Visually inspect the throttle position sensor (TPS) and its wiring for any signs of damage, corrosion, or disconnection. Ensure the connector is securely attached.</li> <li><b>Check TPS Voltage</b>: Using a multimeter, measure the voltage at the TPS connector. The voltage should typically range between 0.5V to 4.5V as the throttle is moved from closed to open position. Any reading outside this range indicates a faulty sensor.</li> <li><b>Test TPS Resistance</b>: Disconnect the TPS and measure the resistance across its terminals. Compare the readings with the manufacturer's specifications. A significant deviation suggests a defective sensor.</li> <li><b>Inspect ECM Connections</b>: Check the connections between the TPS and the Engine Control Module (ECM) for continuity. Ensure there are no open circuits or short circuits.</li> <li><b>Perform ECM Reset</b>: Reset the ECM to clear any stored codes and retest the system. Monitor the TPS readings using a scan tool to ensure they are within the expected range.</li> <li><b>Final Verification</b>: After repairs, perform a road test to ensure the issue is resolved and the DTC code does not reappear.</li></ul>

<p>The DTC code P1120 indicates that the <b>Throttle Position Sensor (TPS)</b> is out of range. This is a <b>critical</b> issue as it can lead to <ul><li>erratic engine performance</li><li>unexpected acceleration or deceleration</li><li>potential stalling</li></ul>. Immediate attention is required to prevent <b>unsafe driving conditions</b> and potential <b>engine damage</b>.</p>