Pcm Code EO14, Shorted Coolant Sensor Circuit: Action:

PCM turns on SERVICE ENGINE SOON light and uses MAT sensor value in place of coolant sensor value all calculations the first 4 minutes of operation. Then a value of 194°F (90°C) is used.

The coolant sensor is a 2-wire sensor with signal voltage coming from PCM to sensor terminal "B" (circuit No. 410), and a sensor reference ground on terminal "A" (circuit No. 976).

As sensor temperature increases, resistance decreases. Signal voltage from PCM to terminal "A" decreases as sensor temperature increases and current flows through sensor element to terminal "A" (sensor ground). Code EO14 sets because PCM assumes coolant temperature cannot be 298°F (148°C) or greater when MAT is 212°F (100°C) or less.

1. With coolant sensor shorted, PCM parameter ED04 should read 148°C or more. If not, sensor is not shorted. See NOTE ON INTERMITTENTS.
2. This checks a shorted coolant sensor or a short in circuit No. 410. If parameter stays at 142°C or greater with sensor unplugged, then short is in circuit No. 410, between pin "B" and PCM terminal E16.
3. Fault is most likely at PCM connector or PCM. See PFI CHART C-1, PCM REPLACEMENT CHECK before replacing PCM.