How to check a MAP?

Maintenance/Repairs
1

'93 camry 4-cyl

It’s having some issues and I suspect a bad MAP sensor. What’s the proper way to check it? I’m assuming it involves a multimeter and possibly a vacuum source. Anyone?



Throwing parts at the car is not an option. It has 225K miles and is going to be replaced in a few months.

Thanks.

2

With a multimeter, back probe the MAP sensor connector and set the meter to read on the 20 VDC scale. Turn the ignition switch to the run position. The sensor output voltage should read 4.75-5.25 VDC. Connect a hand vacuum pump to the vacuum connection on the sensor and apply the following values of vacuum to the sensor to measure the the following voltage drop.

 Inches Hg vacuum_________________________Voltage Drop
      3.94___________________________________.3-.5
      7.87___________________________________.7-.9
      11.81__________________________________1.1-1.3
      15.75__________________________________1.5-1.7
      19.69__________________________________1.9-2.1

Tester

3

And according to my handy dandy Actron sensor tester manual the center connector pin is “signal out”

4

Thanks!

5

Issues? What are they? Some other sensor may have similar “issues”. Are you sure it’s not one of those? What does the engine computer do with the information it gets from the MAP sensor?

6

The MAP sensor controls spark advance and fuel control during acceleration. This sensor basically replaced the vaccuum advance on old type distributors and the accelerator pump on carburators.

Tester