P0117 (2) Chevrolet Uplander I

Ignition ON, engine OFF, disconnect the ECT sensor and observe the ECT parameter for -38°C (-36°F).

1. If over -38°C (-36°F), test the signal circuit of the ECT sensor for a short to ground, a short to any low reference circuit. If the ECT circuits check OK, replace the ECT sensor.
2. If under -38°C (-36°F), test for an intermittent and a poor connection at the ECT sensor. If the ECT circuits check OK, replace the control module.