Code 33 - Map Sensor Signal High: Notes

NOTE: For additional Code 33 information, refer to TSB MANUAL UPDATE-SEC. 6E1/6E2/6E3 CODE 33,34,63,64 (NON-TURBOS) .

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).

NOTE: Test numbers refer to test numbers on diagnostic chart.

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.