How To Fix Code 84 Vauxhall Astra

How to Fix Code 84 Vauxhall Astra


A Vauxhall Astra is a popular compact car known for its reliability and performance. However, like any other vehicle, it may experience issues and display error codes, such as Code 84. If you are facing this error on your Vauxhall Astra, it is essential to understand what it means and how to fix it. This article will guide you through the troubleshooting process and provide step-by-step instructions to resolve Code 84.

Understanding Code 84

Code 84 is a generic error code often associated with the engine management system of a Vauxhall Astra. This code usually indicates a fault detected in the throttle position sensor, which is responsible for monitoring the position of the throttle pedal and sending signals to the engine control unit (ECU). When the throttle position sensor malfunctions or sends inaccurate signals, the ECU may trigger Code 84 and activate the engine warning light on the dashboard.

Troubleshooting Code 84

Before attempting any repairs, it is crucial to diagnose and troubleshoot Code 84 properly. Follow these steps to identify the root cause of the issue:

Step 1: Check for other symptoms

Observe your vehicle for any additional symptoms accompanying Code 84. Common signs may include a lack of power, rough idling, stalling, or difficulty accelerating. Make a note of these symptoms as they can help pinpoint the underlying problem.

Step 2: Use an OBD scanner

Connect an On-Board Diagnostics (OBD) scanner to your Vauxhall Astra’s OBD port, usually located near the steering column. The OBD scanner will retrieve the error codes stored in your vehicle’s ECU. Ensure that you specifically note down Code 84 for reference later in the troubleshooting process.

Step 3: Inspect the throttle position sensor

The throttle position sensor is typically located on the throttle body. It is connected to the throttle plate shaft and equipped with an electrical connector. Start by inspecting the sensor for any visible signs of damage or loose connections. Carefully clean the sensor and its connectors using an appropriate electrical contact cleaner, removing any dirt or grime that may hinder its performance.

Step 4: Test the throttle position sensor

Using a multimeter, test the throttle position sensor for accurate readings. Set the multimeter to the voltage setting and connect the leads to the appropriate terminals of the sensor. Gradually operate the throttle pedal and observe the voltage readings on the multimeter. Consult your vehicle’s service manual or a reputable online source for the specific voltage range expected during different throttle positions. If the readings significantly deviate from the specified range, you may need to replace the throttle position sensor.

Step 5: Check wiring and connections

Thoroughly inspect the wiring harness and connectors associated with the throttle position sensor. Look for any frayed wires, loose connections, or signs of corrosion. Repair or replace any damaged components as necessary, ensuring proper electrical connectivity.

Step 6: Clear the error code

Once you have addressed the potential causes of Code 84, it is important to clear the error code from your vehicle’s ECU. This can be done using the OBD scanner by selecting the option to clear stored error codes. After clearing the code, it is advisable to test drive your Vauxhall Astra to ensure the issue has been resolved and the code does not reappear.


Dealing with error codes in your Vauxhall Astra can be frustrating, but with proper troubleshooting and attention to detail, you can resolve Code 84 and get back on the road. Remember to follow the steps outlined in this article, starting with diagnosing the issue and concluding with clearing the error code. If you have followed all the steps and the problem persists, it is recommended to consult a professional mechanic or your Vauxhall dealership for further assistance. Safe driving!

Leave a Comment