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HOMESERVICE MANUALSMAZDA1999626 ES, 2.5 D, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 26 (ENGINE CONTROLS - SYSTEM & COMPONENT TESTING)ENGINE SENSORS & SWITCHESENGINE COOLANT TEMPERATURE SENSORMIATA
1999 Mazda 626 ES, 2.5 D, Standard

Engine Coolant Temperature Sensor: Miata

1999 Mazda 626 ES, 2.5 D, StandardSECTION Miata
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2002 Mazda Protege5, 2002 Mazda Protege, 2002 Mazda Millenia, 2002 Mazda MX-5 Miata, and 2002 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Coolant temperature sender is part of ECT sensor.

ECT Sensor Testing Procedure  Remove ECT sensor. ECT sensor is located on left side of engine. Place ECT sensor and a thermometer in a container of water. Connect ohmmeter between ECT sensor terminals "A" and "B". See Fig 1 . Slowly heat water. Observe resistance reading at specified temperatures. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR SPECIFICATIONS  table. If resistance is not as specified, replace ECT sensor. If sensor resistance is within specification, check wire harness for short or open circuits. Repair or replace as necessary.

Engine Coolant Sender Testing Procedure  To check coolant temperature sender portion of ECT sensor, measure resistance between ground and ECT sensor terminal "C". See Fig 1 . Resistance should be 160-230 ohms with sensor temperature at 122°F (50°C). If engine coolant sender resistance is within specification, check wire harness for short or open circuits. Repair or replace as necessary.

ENGINE COOLANT TEMPERATURE (ECT) SENSOR SPECIFICATIONS

Temperature - °F (°C) Ohms
Miata
68 (20) 2270-2740
176 (80) 290-340
Millenia, Protege & Protege5
68 (20) 2200-2600
176 (80) 290-340
MPV
68 (20) 2200-2800
176 (80) 290-400
626
68 (20) 35500-39200
176 (80) 7180-7920
Fig 1: Identifying ECT Sensor Terminals (Miata)
G97I07736Courtesy of MAZDA MOTORS CORP.
RENDER: 1.0x

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