DTC 15

- Chart - Code 15 Coolant Sensor Circuit.:

- Wiring Diagram for Code 15 Coolant Sensor Open.:

CODE 15, COOLANT SENSOR OPEN

CIRCUIT DESCRIPTION
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 "3")
c. For a time longer than specified
This could cause detonation on a warm engine due to too much spark advance or poor driveability due to wrong fuel control.

CHART DESCRIPTION
1. Checks to see if problem is still present. If it is, the "SERVICE ENGINE SOON" light will come "ON" and Code 15 will be set.
2. Checks to see if the fault is the coolant sensor or lack of voltage to the coolant sensor. Normally you should have 5 volts across the coolant sensor connector terminals.
3. Determines whether the low voltage at the sensor connector is due to opens in the coolant sensor wires, or in another part of the 5V ref. circuit. Normal voltage should be about 5V from ECM Terminals "3" to "7".
4. Checks resistance of the coolant sensor. If the resistance is within the chart specifications, coolant sensor is not faulty; therefore, check for corrosion at the connector, or low coolant level.