Test Procedure
- Turn ignition on. Using scan tool, check data list item No. 21 (engine coolant temperature sensor). If scan tool value approximately matches engine coolant temperature, problem is intermittent. For trouble shooting, see INTERMITTENT DIAGNOSTIC TROUBLE CODES . If scan tool value does not match engine coolant temperature, go to next step.
- Measure voltage between ground and ECT sensor connector terminal No. 1 (Yellow/Green wire) by backprobing. See Figure. Compare voltage to expected value. See ECT SENSOR VOLTAGES . If voltage is as specified, go to next step. If voltage is not as specified, go to step 5.ECT SENSOR VOLTAGES
Temperature - °F (°C) Volts -4 (-20) 3.9-4.5 32 (0) 3.2-3.8 68 (20) 2.3-2.9 104 (40) 1.3-1.9 140 (60) 0.7-0.9 176 (80) 0.3-0.9 - Turn ignition off. Disconnect ECT sensor connector. Check ECT sensor connector for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step 14. If problem does not exist, go to next step.
- Reconnect ECT sensor connector. Turn ignition on. Using scan tool, check data list item No. 21 (engine coolant temperature sensor). If scan tool value approximately matches engine coolant temperature, problem is intermittent. For trouble shooting, see INTERMITTENT DIAGNOSTIC TROUBLE CODES . If scan tool value does not match engine coolant temperature, replace PCM. Go to step 14.
- Turn ignition off. Disconnect ECT sensor connector. Check ECT sensor connector for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step 14. If problem does not exist, go to next step.
- Turn ignition on. Measure voltage between ground and ECT sensor connector terminal No. 1 (Yellow/Green wire). Voltage should be 4.8-4.9 volts. If voltage is as specified, go to step 8. If voltage is not as specified, go to next step.
- Turn ignition off. Disconnect PCM connector D-108. See Figure. Check PCM connector D-108 for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step 14. If problem does not exist, replace PCM. Go to step 14.
- Turn ignition off. Check for continuity between ground and ECT sensor connector terminal No. 2 (Black wire). If continuity exists, go to step 11. If continuity does not exist, go to next step.
- Check PCM connector D-108 for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step 14. If problem does not exist, go to next step.
- Check for damage or open in Black wire between ECT sensor connector terminal No. 2 and PCM connector D-108 terminal No. 57. If problem exists, repair Black wire. Go to step 14. If problem does not exist, replace PCM. Go to step 14.
- Remove ECT sensor. Immerse sensor portion of ECT sensor in hot water and check resistance between ECT sensor connector terminals. Compare resistance with expected value. See ECT SENSOR RESISTANCES . If resistance is as specified, go to next step. If resistance is not as specified, replace ECT sensor. Go to step 14.ECT SENSOR RESISTANCES
Temperature - °F (°C) k/ohms -4 (-20) 14-17 32 (0) 5.1-6.5 68 (20) 2.1-2.7 104 (40) 0.9-1.3 140-(60) 0.48-0.68 176 (80) 0.26-0.36 NOTE: To install ECT sensor, apply thread sealer to ECT sensor threads and tighten ECT sensor to 15-29 ft. lbs. (19-39 N.m). - Check PCM connector D-108 for loose, damaged, or corroded terminals. If problem exists, repair or replace connector. Go to step 14. If problem does not exist, go to next step.
- With PCM D-108 connector and ECT connector disconnected, check Yellow/Green wire for continuity between ECT sensor connector terminal No. 1 and PCM connector D-108 terminal No. 44. If there is no continuity, repair open in Yellow/Green wire. Go to next step. If problem does not exist, replace PCM. Go to next step.
- Test drive vehicle following OBD-II drive cycle Other Monitor pattern. See OTHER MONITOR under OBD-II DRIVE CYCLES under VERIFYING REPAIRS. Check for DTCs. If DTC P0116 is output, go to 1 and retry diagnostic procedure. If DTC P0116 is not output, inspection is complete.