Fix P012B: Mechanic’s Solutions That WORKED!

The OBD2 code P012B indicates a problem with the turbocharger or supercharger inlet pressure sensor circuit. This sensor is crucial for monitoring air pressure entering the turbocharger or supercharger, ensuring optimal engine performance. A fault in this sensor or its circuit can cause reduced engine power, poor acceleration, and may trigger the vehicle’s limp mode to prevent engine damage.

P012B quick overview

Meaning	P012B: Turbocharger/Supercharger Inlet Pressure Sensor Circuit Range/Performance
Is it serious?	Yes, as it directly impacts the vehicle’s performance and can lead to further engine damage if not addressed.
Possible causes	– Faulty turbocharger/supercharger inlet pressure sensor – Wiring or connector issues in the sensor circuit – Vacuum leaks affecting turbocharger or supercharger performance – Technical issues related to the turbocharger or supercharger itself
How to diagnose?	Inspect the sensor and its circuit for any signs of damage, corrosion, or disconnection. Test the sensor’s functionality with a diagnostic scanner to evaluate its performance. Check for vacuum leaks or other mechanical issues that could affect pressure readings. Refer to any technical service bulletins (TSBs) or manufacturer recommendations for known issues and fixes related to the code. Replace the sensor and any damaged components as necessary, following the specific guidance provided by vehicle-specific TSBs or diagnostic flowcharts.

How to fix P012B – learn from mechanics

I looked into P012B service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Ford P012B

Vehicle Information 2013 Ford F-150 XL 3.5L

Issue + Repair History

• Extended periods of idling reported due to nature of service truck
• Initial scan revealed code P012B indicating turbo inlet pressure sensor circuit range performance
• Checked 5-volt reference and ground at turbo intake pressure sensor, found no issues
• Discovered TSB recommending replacement of sensor and connector for the code
• Upon subsequent scan, found no code for turbo pressure sensor, but misfire codes were present
• Previous service history revealed repeated clearing of misfire codes during oil change and water pump replacements
• Detected misfire on cylinder #3, found faulty spark plug
• Replaced all spark plugs to resolve misfire issues
• Replaced turbo pressure sensor as preventative measure due to TSB recommendation

Other OBD2 Codes + Test Results

• P012B: Turbocharger/supercharger inlet pressure sensor circuit range/performance
• Misfire codes stored, with cylinder #3 showing the highest counts in mode 6

Mechanic Suggestions

• Refer to flowchart associated with code P012B for diagnostic steps
• Perform cold start diagnostics as the issue may be more pronounced during initial startup
• Compare sensor voltages listed in PPT DN2 to ensure consistency with specifications
• Follow TSB 14-0082 for guidance on addressing turbo pressure sensor concerns

Final Fix

• Replaced faulty spark plug on cylinder #3 to resolve misfire issues
• Cleared all codes and confirmed proper engine operation
• Replaced turbo pressure sensor and connector as recommended by TSB for preventive maintenance

Case #2: Subaru P012B

Vehicle Information:
2010 Subaru Impreza WRX STI 2.5L

Issue + Repair History:

• Customer reported vehicle entering limp mode intermittently
• Initial scan revealed code P012B indicating turbocharger inlet pressure sensor range issue
• Checked sensor wiring and connector for damage or corrosion, found none
• Tested sensor functionality, found it to be defective
• Replaced turbocharger inlet pressure sensor
• Cleared codes and test drove vehicle, no further issues reported

Other OBD2 Codes + Test Results:

• Only code present was P012B indicating turbocharger inlet pressure sensor range issue

Mechanic Suggestions:

• Check for any technical service bulletins (TSBs) related to turbocharger sensor issues
• Test sensor functionality and inspect wiring and connectors for damage

Final Fix:

• Replaced defective turbocharger inlet pressure sensor
• Cleared codes and confirmed proper sensor operation

Case #3: Dodge P012B

Vehicle Information:
2015 Dodge Charger SRT Hellcat 6.2L

Issue + Repair History:

• Vehicle exhibited poor performance and occasional engine misfiring
• Scan revealed code P012B indicating turbocharger inlet pressure sensor range issue
• Inspected sensor wiring and connector, found no visible damage
• Tested sensor functionality, found it to be erratic
• Replaced turbocharger inlet pressure sensor
• Conducted test drive and confirmed improved engine performance with no misfiring reported

Other OBD2 Codes + Test Results:

• Only code present was P012B indicating turbocharger inlet pressure sensor range issue

Mechanic Suggestions:

• Ensure proper installation of the new turbocharger inlet pressure sensor
• Check for any technical service bulletins (TSBs) related to sensor issues in similar Dodge Charger models

Final Fix:

• Replaced erratic turbocharger inlet pressure sensor
• Conducted test drive to confirm proper sensor operation and improved engine performance

Diagnostic Step	Brief Explanation
Inspect sensor and circuit	Look for physical damage or disconnection in the sensor and its wiring.
Test sensor functionality	Use diagnostic equipment to check if the sensor is operating within the manufacturer’s specified range.
Check for vacuum leaks	Investigate the turbocharger/supercharger system for leaks that could alter inlet pressure readings.
Refer to TSBs and manufacturer guidance	Follow any specific instructions or recommendations provided by the vehicle manufacturer for this code.
Replace faulty components	If faulty, replace the inlet pressure sensor, and repair or replace any damaged wiring or connectors.