E014

Code E14:

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 476. As the temperature of the sensor increases, sensor resistance decreases. A high coolant temperature will result in low signal voltage on CKT 410. Code E14 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 E37 and E38 are not set.
2. MAT Sensor Value less than or equal to 100°C.

FAILURE CONDITIONS:

Coolant sensor value greater than or equal to 148°C.

ACTION TAKEN:

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

NOTES ON FAULT TREE:

1. With sensor shorted, parameter P.1.4 should read 148°C or greater. If not, then the sensor 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 the sensor pin B and PCM/ECM terminal E16.

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

NOTE ON INTERMITTENTS:

Manipulate CKT 410 wiring, the coolant sensor and PCM/ECM connector while observing PCM/ECM Parameter P.O.4. If the failure is induced, the coolant temperature will jump from its normal value to the shorted reading of 148°C or greater. Repair both the COOLANT and PCM/ECM connectors and ensure that they are latched. If wiring and connector check out OK, substitute a known good coolant sensor and retest.