E015

Code E015 - Coolant Temp. Sensor (Low Temp. Indicated):

Temperature To Resistance Values:

Wiring Diagram for Code E015 - Coolant Temp. Sensor (Low Temp. Indicated):

CODE E015 - COOLANT TEMP. SENSOR (LOW TEMP. INDICATED)

Circuit Description:

The Coolant Temperature Sensor is a thermistor that changes resistance as it's temperature changes. When the engine is cold, the resistance of the sensor is high, as the engine warms, the resistance of the sensor decreases.

The ECM applies 5 volts to terminal "C10". When the engine is cold, (resistance high), the ECM will monitor a high voltage at "C10". As the engine warms, (resistance decreases), the voltage at "C10" will decrease. At normal engine operating temperature, the ECM will monitor from 1 to 1.5 volts at terminal "C10". Coolant temperature is one of the inputs used to control.

a. Fuel Delivery
b. Engine Spark Timing (EST)
c. Knock Control (ESC)
d. Idle (IAC)
e. Convertor Clutch (TCC)
f. Canister Purge (CCP)
g. EGR

Code E015 will set if:

a. Coolant below -34°C (-30°F) for 4 seconds.

If the sensor or circuit is open, the ECM will interpret a coolant temperature of -34°C (-30°F) or below and command the fuel control system FULL RICH. In temperatures above 7°C (20°F), the engine may not start, due to the over rich condition, unless "clear flood" is used (fully depressing accelerator).




Test Description: The following numbered steps correspond with the step numbers on the diagnostic chart.

1. First verify that a problem is present. A display of -30°C or colder indicates a high signal voltage (open circuit).

2. By jumpering connector terminal "A" to "B" a low resistance circuit is created. This should cause the display to read 130°C or hotter if the system is operating properly and both CKTs 410 and 452 are OK.

3. If signal CKT 410 is OK, coolant temperature will be displayed at 130°C or hotter. This result would indicate that fault is in CKT 452, ECM terminal "D12" contact or the ECM.




Diagnostic Aids:

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.

Check For:

a. Poor Connection or Damaged Harness - Inspect ECM harness connectors for backed out terminals "C10" or "D12", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.

b. Intermittent Test - If connections and harness checks out ok, monitor ED04 (Coolant Temperature) display while moving related connectors and wiring harness. If the failure is induced, by "Coolant Temperature" display will abruptly change. This will help to isolate the location of the malfunction.



c. Shifted Sensor - The "Temperature To Resistance Value" scale above may be used to test the coolant sensor at various temperature levels to evaluate the possibility of a "shifted" (mis-scaled) sensor which may result in driveability complaints.