Diagnostic Procedures
- Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC SYSTEM CHECKS. After performing powertrain diagnostic system check, go to next step.
- Check coolant level in coolant reservoir. If engine is low on coolant, diagnose loss of coolant condition and repair or top off as necessary and recheck for DTC. If engine coolant level is okay, go to next step.
- Turn ignition off. Locate and disconnect ECT sensor connector. See Figure. Connect a 3-amp fused jumper wire between terminals of ECT sensor harness connector. Turn ignition on and monitor ECT sensor on scan tool. If scan tool indicates ECT value is less than 280°F (138°C), go to next step. If scan tool indicates ECT value is more than 280°F (138°C), go to step 7.
- Turn ignition off. Disconnect fused jumper. Reconnect 3-amp fused jumper between ground and ECT connector terminal "B" (Yellow wire). Turn ignition on and monitor ECT sensor on scan tool. If scan tool indicates ECT value more than 280°F (138°C), go to next step. If scan tool indicates ECT value is less than 280°F (138°C), go to step 6.
- Repair open or high resistance in Brown wire between ECT sensor connector terminal "A" and PCM connector C1 terminal No. 80. See Figure. After repairs, go to step 10
- Repair open or high resistance in Yellow wire between ECT sensor connector terminal "B" and PCM connector C1 terminal No. 74. See Figure. After repairs, go to step 10.
- Remove ECT sensor from cylinder head. Place ECT sensor and thermometer in pan of water. Heat pan of water and compare water temperature to resistance of ECT. See TEMPERATURE VS. RESISTANCE table. If resistance at temperature is as specified, go to next step. If resistance at temperature is not as specified, go to step 9.
- Reinstall ECT sensor. Problem is not caused by ECT sensor or circuit. Check for proper operation of coolant thermostat and cooling system and repair as necessary.
- Replace ECT sensor. After replacing sensor, go to next step.
- Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2.
- Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.
TEMPERATURE VS. RESISTANCE
| °F (°C) | Ohms |
|---|---|
| 302 (150) | 47 |
| 284 (140) | 60 |
| 266 (130) | 77 |
| 248 (120) | 100 |
| 230 (110) | 132 |
| 212 (100) | 177 |
| 194 (90) | 241 |
| 176 (80) | 332 |
| 158 (70) | 467 |
| 140 (60) | 667 |
| 122 (50) | 973 |
| 113 (45) | 1188 |
| 104 (40) | 1459 |
| 95 (35) | 1802 |
| 86 (30) | 2238 |
| 77 (25) | 2796 |
| 68 (20) | 3520 |
| 59 (15) | 4450 |
| 50 (10) | 5670 |
| 41 (5) | 7280 |
| 32 (0) | 9420 |
| 23 (-5) | 12,300 |
| 14 (-10) | 16,180 |
| 5 (-15) | 21,450 |
| -4 (-20) | 28,680 |
| -22 (-30) | 52,700 |
| -40 (-40) | 100,700 |