LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 1996 >> SVX LSi >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Trouble Codes >> Code 21 - Coolant Temperature Sensor
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Code 21 - Coolant Temperature Sensor

NOTE: For ECM harness connector terminal identification, see Figure.
  1. Remove collector cover and air intake boot. Disconnect coolant temperature sensor harness connector. Using an ohmmeter, check sensor resistance. Resistance should be 30,000 ohms at 68°F (20°C) and 400 ohms at 176°F (80°C). If resistance is as specified, go to next step. If resistance is not as specified, replace coolant temperature sensor.
  2. Turn ignition off. Disconnect ECM harness connectors. Check resistance between ECM harness connector terminal A3 and sensor harness connector terminal No. 1 (Gray/Yellow wire), and between ECM harness connector terminal A21 and sensor harness connector terminal No. 2 (Blue/Black wire)
  3. Resistance should be zero ohms for all circuits. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, check ECM harness connector terminals for good contact. Repair as necessary. If harness connector terminals are okay, replace ECM.
scientia non olet · About LEMON Manuals