FixVault

Diagnostic Aids

When engine is allowed to cool to ambient temperature or overnight, CTS and IAT sensor resistance or temperature may be checked with a scan tester. Resistance readings of components should be close to each other.

Code 23 is set if signal wire is shorted to ground. If code is intermittent, see TESTS W/O CODES article in this section.

INTAKE AIR TEMPERATURE SENSOR RESISTANCE

Temperature: °F (°C) Resistance: Ohms
210 (100) 185
160 (70) 450
100 (38) 1800
70 (20) 3400
40 (4) 7500
20 (-7) 13,500
0 (-18) 25,000
-40 (-40) 100,700
Fig 1: Code 23 Schematic, Intake Air Temperature (IAT) Sensor Ckt. High Temperature Indicated
G91D16991
Fig 2: Code 23 Flow Chart, Intake Air Temperature (IAT) Sensor Ckt. High Temperature Indicated
G91F16993