DTC 23

Fig. 17 Coolant temperature thermal switch test. Low temperature:

Fig. 46 Coolant temperature sensor, temperature-to-resistance curve. 1987 - 88 models:

Diagnostic Code 23
1. Disconnect battery ground cable, then remove air cleaner upper case and air cleaner element
2. Remove air cleaner lower case, then disconnect intake air temperature sensor electrical connector.
3. Remove intake air temperature sensor from air cleaner lower case.
4. Connect temperature sensor to a suitable ohmmeter, then immerse temperature sensing part into water and read resistance on ohmmeter while slowly raising water temperature, Fig. 17. Temperature to resistance relationship should be as shown, Fig. 46.
5. Install intake air temperature sensor into air cleaner lower case, then torque to 5 - 12 ft. lbs.
6. Connect electrical connector to temperature sensor, then install air cleaner lower case. Install air cleaner element, then the air cleaner upper case.
7. Connect battery ground cable.