CODE 15
Trouble Code 15 indicates that the Coolant Temperature Sensor (CTS) is reporting abnormally low readings. CTS is used to control fuel mixture, timing, idle speed, TCC and EGR operation, among others. The thermistor used has a high-resistance when cold, lowering as the coolant warms.
Code 15 will set if:
- temperature reported is < -37.30 deg F (-38.5 deg C)
Typical thermistor resistances expected are:
Deg C Deg F Resistance (ohms)
100 212 177
70 158 332
40 104 1459
20 68 3520
5 41 7280
-5 23 12300
-20 -4 28680
-40 -40 100700
Typical causes may include:
1) Open circuit in CTS-ECM harness
2) Defective Coolant Temperature Sensor
3) Open sensor ground circuit
4) Defective ECM