Code 23

CIRCUIT DESCRIPTION
The engine coolant temperature sensor provides information on engine coolant temperature to the Engine Control Module (TCM). The ECM then feeds this information to the TCM.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.
1. The ECM will set either ECM fault code 14 or 15 if the engine coolant temperature sensor is faulty.
2. Tech-1 displays status of the ECM coolant temperature switch.

DIAGNOSTIC AIDS
Trouble Code 23 sets when the TCM detects a high voltage at terminal 30 after 20 minutes running time (engine warm). Torque Converter Clutch (TCC) operation allowed after 20 minutes. If any ECM fault codes are present, do the diagnosis for those codes first.

CIRCUIT DIAGRAM

Engine Coolant Temp. Sensor Circuit:

CODE 23 DIAGNOSTIC CHART

Code 23 Diagnostic Chart: