Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Code 31, Map Sensor, Open Or Shorted Circuit: Notes
The MAP sensor responds to changes in manifold pressure. ECM receives a signal voltage that varies between 1-1.5 volts at closed throttle idle, to approximately 4-4.5 volts at wide open throttle (low vacuum). If MAP sensor fails, ECM substitutes a fixed MAP value and uses TPS to control fuel delivery.
- Verifies 5-volt reference is available from ECM.
- Verifies ECM is grounding the circuit.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.