DTC 31, EGR Control Pressure/BARO Sensor CKT Low (High Vac): Notes

Manifold Absolute Pressure (MAP) sensor monitors amount of vacuum in EGR circuit and sends a signal back to PCM. Signal is compared to EGR duty cycle calculated by PCM. DTC 31 will set when: actual EGR pressure is less than 15 kPa for 2 seconds. On "G" Series, PCM will default to shutting down EGR system. On "P" Series, PCM will default to a fixed BARO value.

1. This step determines if DTC 31 is result of a hard failure or an intermittent condition.
2. Attaching a jumper wire between harness terminals "B" (EGR control pressure/BARO signal circuit) to "C" (5-volt reference circuit), will determine if sensor is at fault, or if there is a problem with PCM or wiring.
3. Scan tester may not display 5 volts. It is important that PCM recognized voltage as more than 4 volts, indicating that EGR control pressure/BARO signal circuit and PCM are okay.