Code 23, Intake Air Temperature Low: Notes
WARNING: This page is about a different car, the 1994 GMC Sonoma and 1994 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
ECM supplies and monitors a voltage signal (4-6 volts) to sensor. When temperatures are low, sensor resistance is high and ECM will see a high-monitored voltage signal. As temperature increases, sensor resistance decreases and voltage sensed by ECM drops.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- This checks if Code 23 is a hard failure or an intermittent condition. Code 23 will set if engine is running for one minute, MAT sensor temperature is less than -31°F (-35°C) for 12 seconds and speed sensor signal is not present.
- This simulates conditions for a Code 25. If scan tester displays a high temperature, ECM and wiring are not at fault.
- This checks for continuity of sensor signal and ground circuits.