P305C Code - DC/DC Converter Ignition On/Start Switch Circuit Low Voltage
Quick Answer
The Body Control Module (BCM) controls the ignition main relay through the control circuit by applying voltage to the circuit. Common causes include Faulty Power Supply Transformer, Power Supply Transformer harness is open or shorted, Power Supply Transformer circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P305C indicates DC/DC Converter Ignition On/Start Switch Circuit Low Voltage.
- Common causes
- Common causes include Faulty Power Supply Transformer, Power Supply Transformer harness is open or shorted, Power Supply Transformer circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P305C Description
What are the Possible Causes of the DTC P305C?
- Faulty Power Supply Transformer
- Power Supply Transformer harness is open or shorted
- Power Supply Transformer circuit poor electrical connection
How to Fix the DTC P305C?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P305C code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P305C code?
Need more information on how to fix the P305C code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P305C code diagnosed by a professional: Find a repair shop in your area
Information for Specific Makes
- P305C Buick — DC/DC Converter Ignition On/Start Switch Circuit Low Voltage
- P305C Cadillac — DC/DC Converter Ignition On/Start Switch Circuit Low Voltage
- P305C Chevrolet — DC/DC Converter Ignition On/Start Switch Circuit Low Voltage
- P305C GMC — DC/DC Converter Ignition On/Start Switch Circuit Low Voltage
Frequently Asked Questions about P305C Code
1. What are common symptoms of OBDII code P305C (DC/DC Converter Ignition On/Start Switch Circuit Low Voltage)?
- Common symptoms include difficulty starting the vehicle, poor electrical system performance, and potential illumination of the check engine light.
2. What are possible causes of OBDII code P305C?
- Possible causes include a faulty ignition switch, damaged wiring in the ignition circuit, or a malfunctioning DC/DC converter.
3. How can I diagnose the cause of OBDII code P305C?
- Diagnosis typically involves using a multimeter to test the voltage at the ignition switch and DC/DC converter, as well as inspecting the wiring for any damage or loose connections.
4. Can driving with OBDII code P305C cause further damage to the vehicle?
- While it is generally not recommended to drive with this code, prolonged driving may lead to issues with the vehicle's electrical system and potentially cause the vehicle to stall.
5. How can I repair OBDII code P305C?
- Repair may involve replacing the ignition switch, repairing damaged wiring, or replacing the DC/DC converter, depending on the specific cause identified during diagnosis.
6. Is it safe to continue driving my vehicle with OBDII code P305C?
- It is best to address the issue promptly to prevent any potential electrical system failures or stalling while driving.
7. Can a DIY enthusiast fix OBDII code P305C at home?
- Depending on the underlying cause, some DIY enthusiasts may be able to address the issue by following repair guides and using basic tools. However, complex electrical repairs may require professional assistance.
8. How much does it typically cost to repair OBDII code P305C at a mechanic or dealership?
- Repair costs can vary depending on the cause of the issue, but they may range from $100 to $500 or more, including parts and labor.
9. Are there any preventive measures to avoid OBDII code P305C in the future?
- Regular maintenance, such as checking the electrical system and wiring for any signs of wear or damage, can help prevent issues that may trigger this OBDII code.
10. Will resetting the OBDII code P305C turn off the check engine light?
- Simply resetting the code may temporarily turn off the check engine light, but if the underlying issue is not addressed, the light is likely to come back on. It is crucial to diagnose and repair the root cause of the problem.
Discuss the causes and fixes for P305C OBDII Code
Code P305C comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
