How to Solve Detroit GHG14 Engine Idle Does not Work on Thermostat Mode

Here is illustration to guide you how to optimize/solve Detroit EPA07 GHG14 DDEC VI 10 engine idle does not work on Thermostat mode.

 

Preparations:

2024 Detroit Diesel Diagnostic Link DDDL 8.19 8.09 Free Download

JPRO DLA+ 2.0 Adapter

NEXIQ USB Link 2 Adapter

 

Procedures:

Check as follows:

1 With the ignition in the ON position, turn the thermostat on by pressing any button on the display. Does the Optimized Idle Thermostat power up?

1a Yes; Go to step 2.

1b No; disconnect the Optimized Idle Thermostat electrical connector and check pin 6 for vehicle ground and pin 5 for ignition. Repair as necessary.

 

2 Was the CPC recently programmed?

2a Yes; check for proper CPC parameter settings, Refer to section “Optimized Idle” of the A&I Manual (See table below).

2b No; Go to step 3.

 

3 Is the vehicle equipped with an Auxiliary Power Unit (APU) or ParkSmart?

3a Yes; vehicles with an APU or ParkSmart may not use Optimized Idle to control the cab temperatures. If this is the customer’s complaint, refer to the APU or ParkSmart operation instructions.

 

3b No; Go to step 4.

 

4 Disconnect the Optimized Idle Thermostat. Check for voltage at pin 4, harness side. Is voltage greater than two volts?

4a Yes; repair a short to power between CPC connector 3, pin 1 and pin 4 of the Optimized Idle Thermostat connector.

4b No; Go to step 5.

 

5 Check the Optimized Idle Thermostat settings; Refer to section “ Thermostat Operation” of the Optimized Idle User Manual (DDC-SVC-MAN-0019) . Is the Optimized Idle Thermostat properly configured?

5a Yes; install a test CPC. Go to step 6.

5b No; Refer to section “Thermostat Operation” of the Optimized Idle User Manual (DDC-SVC-MAN-0019) . Verify repair.

 

6 Will Optimized Idle work correctly with the test CPC?

6a Yes; replace the CPC.

6b No; Go to step 7.

 

7 Set the Optimized Idle Thermostat mode to cool the cab and put the vehicle on Optimized Idle mode. Using a heat gun, apply heat to the Optimized Idle Thermostat Skin Temperature sensor; refer to OEM literature for sensor location. Did Optimized Idle start the engine to cool the cab?

7a Yes; Refer to section “Optimized Idle” of the A&I Manual (See table below) for proper Optimized Idle parameter configuration.

7b No; Go to step 8.

 

8 Monitor the Optimized Idle Thermostat temperature reading while applying heat to the sensor. Is the reading on the Thermostat display accurate?

8a Yes; replace the Optimized Idle Thermostat.

8b No; Go to step 9.

 

9 Disconnect the Optimized Idle Thermostat electrical connector and measure the resistance between the Optimized Idle Thermostat connector and the Skin Temperature sensor harness side connector. Is the resistance less than 10 ohms?

9a Yes; replace the Skin Temperature sensor.

9b No; repair the circuit.

 

More repair cases for Detroit Diesel engines,please refer to:Detroit Diesel Engine Repair