LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 1999 >> Grand Vitara JS, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0118: Engine Coolant Temperature (ECT) Sensor Circuit High Input >> Diagnosis & Repair Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis & Repair Procedure

  1. Turn ignition off. Disconnect ECT sensor harness connector. Turn ignition on. Using DVOM, measure voltage at ECT sensor harness connector terminal No. 1 (Orange/Black wire). If 4.5-5.5 volts exists, go to next step. If 4.5-5.5 volts does not exist, check Orange/Black wire for open or short to power. See WIRING DIAGRAMS article. If wire is okay, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article. Retest system.
  2. Turn ignition off. Connect a fused jumper wire between ECT sensor harness connector terminals No. 1 (Orange/Black wire) and No. 3 (Gray/Yellow wire). Turn ignition on. Using DVOM, measure voltage between ground and ECT sensor harness connector terminal No. 1 (Orange/Black wire). If less than .15 volt exists, go to next step. If .15 volt or more exists, check Gray/Yellow wires for open or poor connection between ECT sensor harness connector terminal No. 3 and PCM 26-pin connector "B" terminals No. 20 and 21. See WIRING DIAGRAMS article. Repair as necessary. If wiring and connections are okay, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article. Retest system.
  3. Test ECT sensor. See SYSTEM & COMPONENT TESTING article. Replace ECT sensor if resistance is not as specified. See REMOVAL, OVERHAUL & INSTALLATION article. If ECT sensor tests okay, check for poor connection to ECT sensor. If connection is okay, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article. Retest system.
scientia non olet · About LEMON Manuals