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On DDEC III/IV engines there is an Air Temperature Sensor (ATS) mounted to the bottom of the intake manifold. The ATS sends an electrical signal to the ECM indicating the inlet manifold temperature of the air entering the engine. The ECM uses this information to adjust gas flow, control air fuel ratio and in some cases fan control. The ATS provides necessary input to vary hot idle speed and injection timing resulting in improved cold starts and reduced white smoke. See Figure 27804 and see Figure 36033 . ‪

1. Intake Manifold ‪

2. Air Intake Sensor ‪

Air Temperature Sensor (All Diesel Except Heat Exchanger-Cooled Pleasure Craft Marine)

1. Hose ‪

8. Gasket ‪

2. Elbow ‪

9. CAC Matrix ‪

3. Gasket ‪

10. Housing Lower ‪

4. Sleeve ‪

11. Sensor ‪

5. Seal Ring ‪

12. Seal Ring ‪

6. Bolt ‪

13. Air Temperature Sensor ‪

7. Housing Upper ‪

14. Bracket ‪

15. Bolt ‪

Air Temperature Sensor (Heat Exchanger-Cooled Pleasure Craft Marine)

The Series 60G natural gas engine air temperature sensor (ATS) is installed into the air inlet tube. See Figure 27920 . The ATS sends an electrical signal to the ECM indicating air inlet temperature. The ECM uses this information to adjust gas flow and control air fuel ratio. ‪

1. Air Temperature Sensor ‪

Air Temperature Sensor

Repair or Replacement of Air Temperature Sensor

The ATS is non-serviceable, and is replaced as a unit. No adjustment is required. ‪

Removal of Air Temperature Sensor

Remove the ATS as follows: ‪

  1. Disengage locking tang on two-wire connector.
  2. Grasp body of the connector and gently pull it from the socket.
  3. Use the appropriate wrench on the hex portion of the sensor and unscrew it from manifold.

Installation of Air Temperature Sensor

Install the ATS as follows: ‪


Overtightening will distort and crack the sensor body, resulting in sensor malfunction. Damage may not be evident until sensor removal, when body may break apart. ‪

  1. If installing a new ATS, there is no need to use sealer as it is applied during manufacturing. When reinstalling a serviceable ATS, apply Loctite pipe sealant with Teflon PT-7260 or equivalent on all but first two threads.
  2. Install ATS to the intake manifold (diesel) or air inlet tube (natural gas).

    Note: Because of its plastic body, the ATS must be hand started and carefully tightened.

  3. Torque to 11-16 Nm (8-12 lbft).
  4. Carefully fasten connector onto sensor and engage locking tang.
  5. Turn the ignition to the ON position. Observe the DDR for any diagnostic code(s). If any code(s) other than code 25 is logged, refer to the Detroit Diesel Single ECM Troubleshooting Manual (6SE497).