EGR Control Pressure/BARO Sensor Output Check

EGR Control Pressure/BARO Sensor Output Check:

CIRCUIT DESCRIPTION
An Exhaust Gas Recirculation (EGR) control pressure/Barometric Absolute Pressure (BARO) sensor is used to monitor the amount of vacuum in the EGR circuit. It senses the actual vacuum in the EGR vacuum line and sends a signal back to the Powertrain Control Module (PCM). The signal is compared to the EGR duty cycle calculated by the PCM. On vehicles not equipped with EGR, this sensor is only used for a BARO reading.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

NOTE: Be sure to use the same diagnostic test equipment for all measurements.

1. Checks sensor output voltage to the PCM. This voltage, without engine running, represents a barometer reading to the PCM.

^ When comparing Tech 1 scan readings 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.

2. Applying 34 kPa (10" Hg) vacuum to the sensor should cause the voltage to change. Subtract second reading from the first. Voltage value should be greater than 1.5 volts. When applying vacuum to the sensor, the change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.
3. Check vacuum hose to sensor for leaking or restriction. Be sure that no other vacuum devices are connected to the sensor hose.

NOTE: Make sure electrical connector remains securely fastened.

4. Disconnect sensor from bracket and twist sensor by hand (only) to check for intermittent connection. Output changes greater that 0.1 volt indicates a bad connector or connection. If OK, replace sensor.