EGR Control Pressure/BARO Sensor Output Check
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1995 GMC Yukon, 1995 GMC Suburban, 1995 GMC Pickup, 1995 GMC Cab & Chassis, and 1995 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
An EGR control pressure/BARO sensor monitors the amount of vacuum in EGR circuit. It senses actual vacuum in EGR vacuum line and sends a signal back to PCM. The signal is compared to EGR duty cycle calculated by PCM. On vehicles not equipped with EGR, this sensor is only used for a BARO reading.
NOTE:
Test numbers refer to numbers on diagnostic chart.
NOTE:
Use the same diagnostic test equipment for all measurements.
- Checks sensor output voltage to PCM. This voltage, without engine running, represents a barometer reading to PCM. When comparing scan tester reading to a known good vehicle, it is important to compare vehicles which use a sensor having the same color insert or having the same hot stamped number.
- Applying 10" Hg (34 kPa) vacuum to sensor should cause voltage to change. Subtract second reading from the first. Voltage difference should be greater than 1.5 volts. When applying vacuum to sensor, change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.
- Check vacuum hose to sensor for leaks or restriction. Ensure no other vacuum devices are connected to sensor hose.NOTE: Ensure electrical connector remains securely fastened.
- To check for intermittent connection, disconnect sensor from bracket and twist sensor by hand. Output changes greater than .1 volt indicates a bad connector or connection. If okay, replace sensor.