E014

Code E014:

Sensor Circuit:

DESCRIPTION:

The coolant sensor which is located behind the distributor on the thermostat housing, is a thermistor, a sensor whose resistance varies with temperature. The coolant sensor signal is on CKT 410 and sensor ground on CKT 976. As the temperature of the sensor increases, sensor resistance decreases. A high coolant temperature will result in low signal voltage on CKT 410. Code E014 sets because the coolant temperature cannot be greater than 148°C (298°F) when the MAT is less than 100°C (212°F).

TEST CONDITIONS:

1. Codes E037 and E038 clear.
2. MAT Sensor Value 100°C or less.

FAILURE CONDITIONS:

Coolant sensor signal 148°C or greater.

ACTION TAKEN:

1. ECM turns on "SERVICE ENGINE SOON" telltale.
2. ECM uses the MAT sensor values in place of coolant temperature sensor for the first four minutes of engine operation, then the value of 90°C is used.

NOTES ON FAULT TREE:

1. With sensor or wiring shorted, parameter ED04 should read 148°C or greater. If not, then the sensor or wiring is not shorted, see NOTE ON INTERMITTENTS.

2. Checking for sensor shorted or CKT 410 shorted. If the parameter stays at 142°C or greater with the sensor unplugged, then the short is in CKT 410, between sensor pin B and ECM terminal E16.

3. Checking for faulty mating of ECM connector. Fault is most likely at ECM connector or the ECM. Before ECM is replaced, perform "ECM Replacement Check", Chart C-1.

NOTE ON INTERMITTENTS:

Manipulate CKT 410 wiring, the coolant sensor and ECM connector while observing ECM Parameter EDO4. If the failure is induced, the coolant temperature will jump from its normal value to the shorted reading of 148°C, repair the intermittent short to ground on CKT 410. Remove and replace both the COOLANT and ECM connectors and ensure that they are latched. If wiring and connector check out OK, substitute a known good coolant sensor and retest.