Test MAP sensor
Thread Starter
Safety Car
Joined: Mar 2005
Posts: 4,723
Likes: 11
From: Winnipeg Manitoba, Canada
Test MAP sensor
Every so often when scanning my car with Datamaster I get code 33 which is the MAP sensor. How do I test the MAP sensor to make sure its working correctly? Thanks.
Tech Contributor
Joined: Jun 2004
Posts: 20,847
Likes: 959
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Never had to test mine, but it ought to be pretty simple. The sensor outputs a voltage that varies according to the manifold pressure. You could put a Tee in the vacuum line, and a short test harness between the MAP sensor and the vehicle harness, and then hook these up to a vacuum guage and a voltmeter. You should see 4.9-5.1 volts across the supply and ground lines, and a fraction of that on the sensor signal line, depending on your idle vacuum reading.
Instructor
Joined: Jul 2007
Posts: 174
Likes: 0
From: Toronto Ontario
MAP sensor signal voltage
MAP sensor signal voltage should be at around 1-1.5volts at idle and 4-4.5 volts at WOT. Before any test check the hose to the sensor to make sure there is no vacuum leak. If in doubt, replace hose.
Safety Car
Joined: Feb 1999
Posts: 3,504
Likes: 4
From: Mexico Beach FL
I would remove the MAP sensor and use a hand vacuum pump to create a steady vacuum and read the sensor with the scan-tool or a digital voltmeter.
You could vary the vacuum and get a reading at several points (low, medium, and high vacuum).
Tom Piper
You could vary the vacuum and get a reading at several points (low, medium, and high vacuum).
Tom Piper
