Diagnostic Aids

After engine is started, temperature should rise steadily to about 203°F (95°C) and then level off when thermostat opens.

If Codes 14 and 21 are stored at same time, an open could exist in Gray/Yellow wire.

When replacing ECT sensor, check TEMPERATURE TO RESISTANCE VALUES table. A "shifted" sensor could result in poor driveability complaints.

Fig 1: Code 14 - Schematic Engine Coolant Temperature Sensor Circuit, Low Temp. Indicated

Fig 2: Code 14 - Flow Chart Engine Coolant Temperature Sensor Circuit, Low Temp. Indicated