With Speed Density Update

Code 33:

Manifold Absolute Pressure (MAP) Sensor Circuit:

CIRCUIT DESCRIPTION
The Manifold Absolute Pressure (MAP) sensor responds to changes in manifold pressure (vacuum). The Electronic Control Module (ECM) receives this information as a signal voltage that will vary from about 1.0 - 1.5 volts at idle (high vacuum) to 4.0 - 4.5 volts at wide open throttle (low vacuum).

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

1. Code 33 will set when:
^ Engine running
^ Manifold pressure greater than 74 kPa (A/C "OFF") 83.4 kPa (A/C "ON")
^ Throttle angle less than 2% with vehicle in 1st gear or 6% in any other gear
^ Conditions met for 4.8 seconds

NOTE: Engine misfire or a low unstable idle may set Code 33.

2. With the MAP sensor disconnected, the ECM should see a low voltage if the ECM and wiring are OK.

DIAGNOSTIC AIDS
An open in circuit 452 or the connection will result in a Code 33. Ignition "ON" engine "OFF", voltages should be within the values shown in the table on the chart. To test the MAP sensor, refer to Diagnostic Charts / Chart C-1D and Diagnosis by Symptom / Intermittents. - Intermittent Malfunctions