Code 23, Mat Sensor Temp. Low - 4.3L Turbo

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.

A scan tester cannot be used to diagnose this fault due to the ECM transmitting a default value when code is set. Code will set due to an open sensor, wire, or connections. This step determines if the wiring and ECM are okay.
If resistance is greater than 25 k/ohms, replace sensor.

Fig 1: CODE 23 - MAT Sensor Temp. Low Schematic (4.3L Turbo)

Fig 2: CODE 23 - MAT Sensor Temp. Low Flowchart (4.3L Turbo)