DTC P1401: EGR Temperature Sensor: Procedure

Turn ignition off. Disconnect EGR temperature sensor harness connector. See Figure. Turn ignition on. Measure voltage between ground and EGR temperature sensor harness connector terminal No. 1 (White wire). If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, repair open or short between ECM and EGR temperature sensor. Retest system.
Turn ignition off. Check continuity between engine ground and EGR temperature sensor harness connector terminal No. 2 (Black wire). Also, check circuit for short to voltage. See WIRING DIAGRAMS article. Repair circuit as necessary and retest system. If ground circuit is okay, go to next step.
Remove EGR temperature sensor. Measure resistance between EGR temperature sensor terminals, with EGR temperature sensor at specified temperatures. See EGR TEMPERATURE SENSOR RESISTANCE table. If resistance is as specified, go to next step. If resistance is not as specified, replace EGR temperature sensor and retest system.
No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.

EGR TEMPERATURE SENSOR RESISTANCE