Section 40.1
SPN 412/FMI 3

This diagnosis is typically EGR temperature circuit failed high.‪

Section 40.1.1
Open Circuit/Short to Power Check

Check as follows:‪

1. Turn the ignition the ON (key ON, engine OFF).
2. Check for multiple codes.
   1. If codes 1636/3, 2629/3 and 412/3 are active at the same time, .
   2. If only fault 412/3 is active, go to step 5 .
3. Disconnect the Intake Air Temperature Sensor.
4. Measure the voltage between pin 1 of the Intake Air Temperature Sensor and ground.
   1. If the voltage is greater than 2.75 volts, repair the short to power between pin 52 of the MCM 120–pin connector and the Intake Air Temperature Sensor, the Turbo Compressor Out Sensor and the EGR Temperature Sensor. Refer to "40.1.1.1 Verify Repairs" .
   2. If no voltage is present on pin 1 of the Intake Air Temperature Sensor, repair the open circuit between pin 52 of the MCM 120–pin connector and the Intake Air Temperature Sensor, the Turbo Compressor Out Sensor and the EGR Temperature Sensor. Refer to "40.1.1.1 Verify Repairs" .
5. Disconnect the EGR Temperature Sensor.
6. Measure the resistance across pins 1 and 2 of the EGR Temperature Sensor.
   1. If the resistance is not within the range listed in Table "EGR Temperature Sensor Resistance" , replace the EGR Temperature Sensor. Refer to "40.1.1.1 Verify Repairs" .
   2. If the resistance is within the range listed in Table "EGR Temperature Sensor Resistance" , go to step 7 .

   Temperature (°F)‪	Temperature (°C)‪	Maximum Resistance (KΩ)‪	Minimum Resistance (KΩ)‪
   32‪	0‪	1053.00‪	634.00‪
   50‪	10‪	601.75‪	367.98‪
   68‪	20‪	357.27‪	224.97‪
   86‪	30‪	219.54‪	142.08‪
   104‪	40‪	139.17‪	92.40‪
   122‪	50‪	90.75‪	61.72‪
   140‪	60‪	60.72‪	42.23‪
   158‪	70‪	41.58‪	29.55‪
   176‪	80‪	29.10‪	21.09‪
   194‪	90‪	20.77‪	15.34‪

   Table 1. EGR Temperature Sensor Resistance
7. Turn the ignition ON (key ON, engine OFF).
8. Measure the voltage between pins 1 and 2 of the EGR Temperature Sensor harness connector.
   1. If the voltage is between 2.75 and 3.25 volts, refer to "40.1.1.1 Verify Repairs" .
   2. If the voltage is less than 2.75 volts, go to step 9 .
9. Measure the voltage between pin 2 of the EGR Temperature Sensor harness connector and ground.
   1. If the voltage is between 2.75 and 3.25 volts, repair the open circuit between pin 1 of the EGR Temperature Sensor harness connector and pin 52 of the 120–pin MCM connector. See Figure "EGR Temperature Sensor" . Refer to "40.1.1.1 Verify Repairs" .
   2. If the voltage is less than 2.75 volts, repair the open circuit between pin 2 of the EGR Temperature Sensor harness connector and pin 83 of the 120–pin MCM connector. See Figure "EGR Temperature Sensor" . Refer to "40.1.1.1 Verify Repairs" .
   

   Figure 1. EGR Temperature Sensor

Section 40.1.1.1
Verify Repairs

Verify repairs as follows:‪

1. Turn ignition OFF.
2. Reconnect any electrical connections that were disconnected to perform the diagnosis.
3. Clear codes with DDDL 7.0 or latest version.
4. Start and bring engine up to operating temperature (over 140°F/60°C).
5. Verify operation is satisfactory and no warning lamps illuminate. If warning lamps illuminate, troubleshoot the codes. If assistance is required, call the Detroit Diesel Customer Support Center at 313–592–5800.