DTC P1401 - EGR Temperature Sensor
- Check Power Supply - Turn ignition off. Disconnect EGR temperature sensor harness connector. See Fig 1. Turn ignition on. Using a voltmeter, measure voltage between ground and EGR temperature sensor harness connector terminal No. 1 (Red/Black wire). If voltage is not about 5 volts, repair fault in Red/Black wire. If voltage is about 5 volts, go to next step.
- Check Ground Circuit - Turn ignition off. Using an ohmmeter, check continuity between engine ground and EGR temperature sensor harness connector terminal No. 2 (Black wire). If no continuity exists, repair open in Black wire. If continuity exists, go to next step.
- Check EGR Temperature Sensor
- Ensure sensor is not damaged or contaminated. Check ECM and EGR temperature sensor harness connectors for damage, corrosion or pushed-out pins. Repair if necessary. If no problems are found, ensure ignition is off. Measure resistance between EGR temperature sensor connector terminals as follows:
- With temperature at 32°F (0°C), resistance should be 7.9-9.7 megohms.
- With temperature at 122°F (50°C), resistance should be .57-.70 megohms.
- With temperature at 212°F (100°C), resistance should be .08-.10 megohms.
If resistance is not as specified, replace EGR temperature sensor. If resistance is as specified, disconnect harness connectors in circuit and check for damage or corrosion. If fault is still present, replace EGR temperature sensor.