The P2538: Ignition Switch Accessory Position Circuit High code indicates that there is an abnormally high voltage or signal present in the ignition switch accessory position circuit. This can be caused by a faulty ignition switch, wiring problems such as a short to power, or issues with the connectors. A high voltage reading can lead to improper functioning of electrical systems connected to the accessory circuit.
P2538 – Quick Overview
Code | Information |
---|---|
Meaning | P2538: Ignition Switch Accessory Position Circuit High |
Is it serious? | Moderately serious. High voltage can lead to erratic behavior of accessory components, potentially damaging them or causing operational issues. |
Possible causes | – High voltage or signal in the ignition switch accessory position circuit – Faulty ignition switch – Wiring or connector issues |
How to diagnose? | – Measure the voltage in the ignition switch accessory position circuit – Inspect and test the ignition switch – Check wiring and connectors – Replace faulty components if needed |
Code Meaning
The P2538: Ignition Switch Accessory Position Circuit High code means that the detected voltage in the accessory position of the ignition switch circuit is higher than expected. This could be due to a short to power, an issue with the ignition switch itself, or wiring issues. High voltage can disrupt the functioning of accessory components, leading to unexpected behavior or damage.
Step-by-step diagnostic guide
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to determine if there are other related codes present. Additional codes can provide more context about any other issues that could be affecting the accessory circuit or electrical system. | OBD-II Scanner |
Measure Voltage in the Accessory Position Circuit | Use a multimeter to measure the voltage in the ignition switch accessory position circuit. Compare the readings to manufacturer specifications to determine if the voltage is higher than expected. | Multimeter |
Inspect the Ignition Switch | Visually inspect the ignition switch for any visible signs of damage or wear. Make sure it operates smoothly between positions. Look for cracked housing or loose connections that could be causing incorrect voltage. | Flashlight, Safety Gloves |
Check Wiring and Connectors | Inspect the wiring and connectors related to the ignition switch accessory circuit. Look for signs of damage, such as frayed wires or poor connections, which could lead to excessive voltage in the circuit. Repair or replace any damaged wiring or connectors. | Flashlight, Multimeter |
Test the Ignition Switch for Proper Voltage Output | Use a multimeter to test the voltage output from the ignition switch in the accessory position. Verify that the voltage is within the acceptable range specified by the manufacturer. If the switch is providing higher voltage, replace the ignition switch. | Multimeter |
Inspect for Short Circuits to Power | Inspect the wiring for any possible shorts to the power supply. A short circuit can cause the accessory circuit to receive more voltage than intended, leading to a high voltage issue. | Multimeter |
Verify Voltage Supply and Ground Integrity | Use a multimeter to verify the power supply and ground connections. Ensure that there are no issues that could lead to a high voltage reading in the circuit. An improper or inconsistent power supply or ground connection could be responsible for the error. | Multimeter |
Inspect Fuse Box and Relays | Check the fuses and relays related to the ignition switch accessory circuit. Ensure that no fuses are blown and that all related relays are functioning properly. Replace any components that appear faulty. | Fuse Puller, Multimeter |
Replace Faulty Components | Replace any identified faulty components, such as the ignition switch, wiring, or connectors. Use only OEM parts to ensure compatibility and reliability of the accessory circuit. | Replacement Parts, Vehicle Owner’s Manual |
Clear the Code and Test the System | After completing repairs, clear the P2538 code using an OBD-II scanner. Start the vehicle and test the ignition switch in the accessory position to confirm proper function and that voltage levels are within the correct range. | OBD-II Scanner, Vehicle Owner’s Manual |
Recheck for Codes | Re-scan the vehicle to confirm that the P2538 code has not returned. If the code persists, further diagnostics may be needed to identify any additional underlying issues. | OBD-II Scanner |

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Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)