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TCU Code 3 - Coolant Sensor

  1. Check for open or short circuit in CTS or harness. Check that continuity exists between TCU harness pin No. 10 and pin No. 106 at CTS connector, and pin No. 21 and pin No. 109. See Fig 1 .
  2. Check CTS. If resistance values are incorrect, replace CTS. See COOLANT TEMPERATURE SENSOR SPECIFICATIONS  table.
COOLANT TEMPERATURE SENSOR SPECIFICATIONS

Temperature Ohms Resistance
68°F (20°C) 2210-2690
86°F (30°C) 1570-1730
140°F (60°C) 550-610
Fig 1: Checking Coolant Sensor
G94708