Powertrain Controls - ECM/PCM

Code 33 - MAP Sensor Circuit Signal Voltage High (Low Vacuum):

Wiring Diagram For Code 33 - MAP Sensor Circuit (Signal Voltage High - Low Vacuum):

CODE 33 - MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT


CIRCUIT DESCRIPTION:

The manifold absolute pressure (MAP) sensor responds to changes in manifold pressure (vacuum). The ECM receives this information as a signal voltage that will vary from about 1 to 1.5 volts at idle to 4-4.5 volts at wide open throttle.



TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Code 33 will set when:

^ Signal is too high for a time greater than 6 seconds.
Engine misfire or a low unstable idle may set Code 33.
^ Engine Running:
Manifold pressure greater than 75.3 kPa (A/C "OFF") 81.2 kPa (A/C "ON") Throttle angle less than 2% Conditions met for 2 seconds.

2. With the MAP sensor disconnect the ECM; should see a low voltage if the ECM and wiring is OK.


DIAGNOSTIC AIDS:


The "Altitude To Voltage" scale above may be used to test the MAP sensor at a specific altitude level to evaluate the possibility of a "slewed" (mis-scaled) sensor. A "slewed" sensor could result in poor driveability complaints.

Engine misfire or a low unstable idle may set Code 33. Disconnect MAP sensor and system will go into backup mode. If the misfire or idle condition remains, SEE DIAGNOSIS BY SYMPTOM - NO TROUBLE CODES STORED.