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 33 - Map Sensor Signal High: Notes
The Manifold Absolute Pressure (MAP) sensor responds to changes in manifold pressure (vacuum). The ECM receives this information as a voltage signal which will vary from about 1-1.5 volts at idle (high vacuum/low pressure) to about 4-4.5 volts at wide open throttle (low vacuum/high pressure).
- Code 33 will set if the following conditions are met:
- Engine running.
- Manifold pressure is greater than specified.
- Throttle angle is less than 2 percent.
- All conditions have been met for 4-5 seconds. Engine misfire, or a low unstable idle may set a Code 33.
- With the MAP sensor disconnected, the ECM and "Scan" tester should recognize a low voltage. If low voltage is shown on tester, ECM and harness are not at fault.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra 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.