Troubleshoot a MAP sensor by checking for common issues such as blocked vacuum hoses, loose wires and default computer connections. The MAP sensor is positioned beside the firewall or the engine compartment on the passenger side. Start by examining the simplest options before proceeding to the complex issues.
First, inspect the vacuum hose attached to the sensor to ensure it is free of obstructions and operating efficiently. Check to be sure that the sensor’s electrical connector is in a good condition and all wires around it are firm. Use a voltmeter to make sure that the sensor is configured correctly.
If a MAP sensor has communication issues, use a voltmeter to determine if the problem is caused by an electrical fault. Remove the electrical connections from the back of the sensor, and turn on the ignition. Measure the reference voltage by touching the reference wire with the meter’s lead. If the reference voltage is above 5 volts, the connection is out of specification. Remove the wiring, and replace it with some fresh pieces.
If a MAP sensor uses a frequency, use a tachometer to determine the source of the issue. Plug an electrical connection into the sensor, and affix the tachometer to the signal and ground wires. If the frequency is above 5 volts, there is an issue with the sensor. If the above repair methods do not solve the problem, contact an MAP expert for assistance.