LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Honda >> 1985 >> Prelude Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> EGR System >> Component Testing >> THERMOSENSOR
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Component Testing: THERMOSENSOR

  1. Thermosensor resistance must be checked both cold and hot. Coolant temperature must be less than 104°F (40°C) to perform cold resistance check. Disconnect vacuum hose No. 19 from charcoal canister. If there is no vacuum at idle, thermovalve B is open and thermosensor resistance check can be performed.
  2. Disconnect connector at control unit. Check for resistance between Blue/Yellow and Brown/Black terminals. Resistance should be above 1000 ohms. Run engine until cooling fan comes on and check resistance again. Resistance should be about 200 ohms.
  3. If resistance is not within specifications, replace thermosensor and retest. If ohmmeter shows no continuity, check wires. If there are no defects, replace thermosensor and retest.
scientia non olet · About LEMON Manuals