Rodeo S 4WD V6-3165cc 3.2L SOHC (6VD1) (1997)
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Manifold Absolute Pressure Sensor: Testing and Inspection
MANIFOLD ABSOLUTE PRESSURE (MAP) OUTPUT CHECK
Circuit Description
The manifold absolute pressure (MAP) sensor measures the changes in the intake MAP which result from Engine load (intake manifold vacuum)
and Engine speed changes; and converts these into a voltage output. The Powertrain Control Module (PCM) sends a 5-volt reference voltage to
the MAP sensor. As the MAP changes, the output voltage of the sensor also changes. By monitoring the sensor output voltage, the PCM knows the
MAP. A lower pressure (low voltage) output voltage will be about 1 - 2 volts at idle. Higher pressure (high voltage) output voltage will be about
4.0 - 4.8 volts at wide open throttle. The MAP sensor is also used, under certain conditions, to measure barometric pressure, allowing the PCM to
make adjustments for different altitudes. The PCM uses the MAP sensor to diagnose proper operation of the Exhaust Gas Recirculation (EGR)
system, in addition to other functions.
Test Description
Number(s) below refer to the step number(s) in the Diagnostic Test:
NOTE: Be sure to use the same diagnostic test equipment for all measurements.
1. When you compare the Scan Tool readings to a known good vehicle, it is important to compare vehicles that use MAP sensors that have the same
color insert (2) or the same "Hot Stamped" (1) number. (Numbers refer to the image.)
2. Applying 34 kPa (10 Hg) vacuum to the MAP sensor should cause the voltage to be 1.5 - 2.1 volts less than the voltage at step 1. Upon applying
vacuum to the sensor, the change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.
3. Check the vacuum hose to the sensor for leaking or restriction. Be sure that no other vacuum devices are connected to the MAP hose.
NOTE: Make sure the electrical connector remains securely fastened.
4. Disconnect the sensor from the bracket. Twist the sensor with your hand to check for an intermittent connection. Output changes greater than 0.10
volt indicate a bad sensor.
Diagnostic Test
1. a. Turn the ignition "OFF" and leave it "OFF" for 15 seconds.
b. Ignition "ON". Don't crank Engine.
c. The Scan Tool should indicate a manifold absolute pressure (MAP) sensor voltage.
