ECM Code EO14 - Shorted Coolant Sensor Circuit: Notes

TEST CONDITIONS:  Codes EO37 and EO38 are clear. MAT sensor value less than or equal to 105°C.

FAILURE CONDITIONS:  Coolant sensor value greater than or equal to 142°C (sensor signal shorted to ground).

ACTION:  ECM turns on "ENGINE CONTROL SYSTEM" light. ECM commands BCM to display "SERVICE SOON" message on CCDIC panel. ECM turns off both AIR management solenoids. ECM uses MAT sensor value in place of coolant sensor value for all calculations.

The coolant sensor is a variable thermistor. The coolant sensor is a 2-wire sensor with a signal voltage coming from the ECM to sensor pin "B" (circuit No. 410PC), and a sensor reference ground on pin "A" (circuit No. 476PC).

As temperature of sensor increases, sensor resistance decreases. Signal voltage from ECM to pin "A" decreases as sensor temperature increases and current flows through sensor element to pin "A" (sensor ground). Code E014 sets because ECM assumes that coolant temperature can't be 142°C or greater when MAT is 105°C or less (sensor signal shorted to ground).

1. With coolant sensor shorted, parameter ED04 should read 142°C or more. If not, then sensor is not shorted. See NOTE ON INTERMITTENTS.
2. This step checks for a shorted coolant sensor or for a short in circuit No. 410. If parameter stays between 142-151°C with the sensor unplugged, then short is in circuit No. 410.
3. Fault is most likely at ECM connector or ECM. See CHART C1 - ECM REPLACEMENT CHECK before replacing ECM.