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Home >> Suzuki >> 1999 >> Grand Vitara JS+, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0125: Insufficient Engine Coolant Temperature (ECT) To Enter Closed Loop >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). Start engine and warm to operating temperature. Idle engine. If ECT reading is less than 88°F (31°C), go to next step. If ECT reading is more than 88°F (31°C), go to step  4 .
  2. Turn ignition off. Connect a jumper wire between ECT sensor harness connector terminals No. 1 (Orange/Black wire) and No. 3 (Gray/Yellow wire). Turn ignition on. If ECT reading is 401°F (205°C), go to next step. If ECT reading is not 401°F (205°C), check for open in Orange/Black wire or Gray/Yellow wire between ECT sensor harness connector and PCM. See WIRING DIAGRAMS article. Repair as necessary. If Orange/Black wire and Gray/Yellow wire 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, go to next step.
  4. Check thermostat operation. If heater takes a long time to become effective, or coolant flows into radiator on cold start, remove thermostat for inspection. Replace as necessary and retest system. If thermostat operates properly, replace PCM. See REMOVAL, OVERHAUL & INSTALLATION article. Retest system.
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