DTC 15

Fig. 016 - WIRING DIAGRAM for Code 15 Coolant Sensor Circuit (Signal Voltage High). VIN N, VIN T:

CODE 15

COOLANT SENSOR CIRCUIT

(SIGNAL VOLTAGE HIGH)

4.3L VIN "T"

5.7L VIN "N"

Code 15 means the ECM has seen the resistance of the Coolant Sensor Circuit too high as follows:
a. High resistance (Cold Engine Temperature)
b. Or high voltage (at ECM Terminal "W")
c. Or open coolant sensor circuit.
d. For a time longer than specified

Fig. 015 - Chart For Code 15 Coolant Sensor Circuit (Signal Voltage High).:

1. This step determines whether the fault is at the coolant sensor or elsewhere in the circuit. Normal voltage should be about 5 volts in the circuit. (4 Volts or over)
2. This step checks for an open circuit between the ECM. Term "J" and the coolant sensor. The coolant sensor is not connected during the test.
3. Determines if problem is in coolant sensor circuit to ECM terminal "W" or ECM. A Voltage reading of under 4 Volts would indicate poor contact at ECM Terminal "W" or a faulty ECM. A reading of 4 Volts or over would indicate an open coolant sensor signal lead to 'ECM Terminal "W".