The turbocharger/supercharger inlet pressure sensor A sits ahead of the compressor – between air filter and turbocharger, or on GM's supercharged V8 between throttle and supercharger. It is an analogue 5 V pressure sensor used for the compressor pressure ratio, filter restriction and cross-checks with the other pressure sensors. P012D means the signal voltage is above its upper limit – typically the signal wire shorted to the 5 V reference or battery voltage, or an open sensor ground that lets the signal rise to the reference. GM's supercharged LT4/LT5 sets it above 97 % of the reference (about 124 kPa) with 320 of 400 samples failing, monitored continuously; two trips on the LT4, one on the 2019 LT5. FCA documented false settings on the 2019 Jeep Wrangler 2.0 turbo, fixed by new engine software. The control module substitutes a modelled or ambient value and may limit boost.
Medium severity. Can I keep driving?Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
Symptoms
- Check engine light on
- Reduced power or limp mode possible
- Often no noticeable symptoms
Most likely causes
- Signal wire shorted to 5 V reference or battery voltage
- Sensor ground open or connector corroded
- Sensor faulty internally
- Control module software (false setting)
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P012D means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 1: Air and fuel
- 2D: Specific fault in that system
Frequently asked questions
Can I keep driving with code P012D?
Drive without demanding power and go to a repair shop soon. If you see a lot of blue smoke or hear a metallic noise, shut off the engine.
What causes code P012D?
The most common causes are: signal wire shorted to 5 V reference or battery voltage; sensor ground open or connector corroded; sensor faulty internally.
Related codes
- P012ATurbocharger/Supercharger Inlet Pressure Sensor A Circuit
- P012BTurbocharger/Supercharger Inlet Pressure Sensor A Circuit Range/Performance
- P012CTurbocharger/Supercharger Inlet Pressure Sensor A Circuit Low
- P012ETurbocharger/Supercharger Inlet Pressure Sensor A Circuit Intermittent/Erratic
- P0238Turbocharger/Supercharger Boost Sensor A Circuit High
- P0108Manifold Absolute Pressure/Barometric Pressure Sensor Circuit High
Sources
- law.cornell.edu: 13 CCR 1968.2
- gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
- gsi.ext.gm.com: 19OBDG03A Diagnostics
- static.nhtsa.gov: MC 10177537 9999
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.