DDEC III/IV Single ECM Troubleshooting

Section 10.10 Engine Brake Inoperative

Section 10.10
Engine Brake Inoperative

The following procedure will troubleshoot DDEC controlled Engine Brake Inoperative.‪

Section 10.10.1
Engine Brake Inoperative

Perform the following steps to troubleshoot the inoperative engine brake:‪

  1. Turn ignition ON.
  2. Plug in DDR.
  3. View Diagnostic Data List to see if the correct application is programmed into the ECM.
  4. Next to Engine Brake, the display should read ON or OFF. If it reads N/A, the DDC mainframe must be changed and the ECM must be reprogrammed after the change is made.
  5. If the ECM is correctly configured, go to the view calibration area with the DDR and check to ensure that the two required inputs (Engine Brake Low and Engine Brake Medium) are configured.
  6. If the inputs are not configured, or incorrectly configured, this must be corrected using the DDEC reprogramming station.
  7. If the inputs are configured correctly, print or write down the inputs and outputs for future reference. Refer to "10.10.2 Check Switches" . Refer to the appropriate Application and Installation manual for engine brake operation.

Section 10.10.2
Check Switches

Perform the following steps to troubleshoot the switches:‪

  1. Turn ignition ON.
  2. Plug in DDR.
  3. Select Switch Light status - Inputs.
  4. View DDR display of Eng Brk Low and Eng Brk Med.

    Note: Set brake dash switch position on low.

    1. If Eng Brake Low is ON and Eng Brake Med is OFF, refer to "10.10.3 View Diagnostic Data Reader Display" .
    2. If Eng Brake Low is ON and Eng Brake Med is ON, medium and low inputs are shorted to each other. Repair. Refer to "10.10.9 Verify Repairs" .
    3. If Eng Brake Low is OFF and Eng Brake Med is ON, input wires are reversed. Correct and refer to "10.10.9 Verify Repairs" .
    4. If Eng Brake Low is OFF and Eng Brake Med is OFF, refer to "10.10.4 Check for Open" .
  5. Turn brake enable dash switch on.

Section 10.10.3
View Diagnostic Data Reader Display

Perform the following steps to troubleshoot the inoperative engine brake:‪

  1. View DDR display.

    Note: Set brake dash switch position on medium.

    1. If Eng Brake Low is OFF and Eng Brake Med is ON, refer to "10.10.5 View Calibration - Engine Configuration" .
    2. If Eng Brake Low is ON and Eng Brake Med is ON, medium and low inputs are shorted to each other. Repair. Refer to "10.10.9 Verify Repairs" . If this is a Series 55 engine, refer to "10.9.5 Check for Short" .
    3. If Eng Brake Low is ON and Eng Brake Med is OFF, input wires are reversed. Correct and refer to "10.10.9 Verify Repairs" .
    4. If Eng Brake Low is OFF and Eng Brake Med is OFF, refer to "10.10.4 Check for Open" .

Section 10.10.4
Check for Open

Perform the following steps to check for an open circuit:‪

  1. Turn ignition OFF.
  2. Turn engine brake switch to low.
  3. Measure resistance between the engine brake low switch and a good ground (ECM side).
  4. Set switch to Med. Measure resistance between medium input and a good ground.
    1. If the measured resistance is less than 10,000 Ω, either the switch is bad or the wire from the switch to the battery ground is bad. Replace the switch or repair the break.
    2. If the measured resistance is greater than 10,000 Ω or open, an open circuit exists in the input wire. Repair the break. Refer to "10.10.9 Verify Repairs" .

Section 10.10.5
View Calibration - Engine Configuration

Perform the following steps to view calibration - engine configuration:‪

  1. Go to View Cal-Eng Configuration. Check status of Eng Brk Serv Brk and Eng Brk mph. If Eng Brk Serv Brk indicates YES, or Eng Brk Min mph has number other than "0", check with the operator to ensure he or she understands how these functions operate.
    1. If the Eng Brk Serv Brk indicates YES, the application of service brake is required for engine brake operation.
    2. If the Eng Brk Min mph has a number other than "0", the brakes will not operate below this mph.
    3. Note: These two functions may work separately or together.

    4. If the Eng Brk Svc Brk indicate No, and Eng Brk Min mph indicate 0, refer to "10.10.6 Check Engine Brake Operation" .

Section 10.10.6
Check Engine Brake Operation

Perform the following steps listed in Table "Engine Brake Operation" to check out the brake and clutch switch, and the wiring. ‪

Note: If table below leads to section 10.11, troubleshoot clutch and brake inputs. Then check operation of engine brake. If engine brake is still inoperative, refer to "10.10.7 Check Brake Solenoids" .

  1. Turn ignition ON. Engine must not be running.
  2. Plug in DDR. Select switch/light status.

Step

Brake Pedal

Clutch Pedal

DDR Readout Looked At

DDR Display

Status OK

Reference

1.‪

Released‪

Released‪

Service Brake (Release)‪

On‪

Off‪

Yes‪

No‪

refer to Step 2‪

refer to "10.11 Miscellaneous Digital Input Fault"

2.‪

Depressed‪

Released‪

Service Brake Release‪

On‪

Off‪

No‪

Yes‪

refer to "10.11 Miscellaneous Digital Input Fault"

refer to Step 3‪

3.‪

Released‪

Released‪

Clutch Release‪

On‪

Off‪

Yes‪

No‪

refer to Step 4‪

refer to "10.11 Miscellaneous Digital Input Fault"

4.‪

Released‪

Depressed‪

Clutch Release‪

On‪

Off‪

No‪

Yes‪

refer to "10.11 Miscellaneous Digital Input Fault"

refer to "10.10.7 Check Brake Solenoids"

Table 1. Engine Brake Operation

Section 10.10.7
Check Brake Solenoids

Perform the following steps to troubleshoot the brake solenoids:‪

  1. Check engine brake solenoids. Refer to OEM guidelines.
    1. If solenoids are okay, refer to "10.10.8 Verify Conditions" .
    2. If solenoids are bad, repair or replace the solenoids. Refer to "10.10.9 Verify Repairs" .

Section 10.10.8
Verify Conditions

Perform the following steps to verify conditions:‪

  1. Verify proper conditions are being met to enable engine brake:
    1. TPS % = 0 %
    2. Pulse width = 0 (or less)
    3. Engine speed >850 r/min
    4. Clutch release (input) = ON (if configured)
    5. Engine brake disable (input) = OFF (Auto Trans)
  2. Are the conditions listed in 1a through 1e met?
    1. If conditions are not met, correct the problem (i.e. TPS). Refer to "10.10.9 Verify Repairs" .
    2. If the conditions are met, reprogram the ECM. Contact the OEM for possible TPS repair. Then, refer to "10.10.9 Verify Repairs" .

Section 10.10.9
Verify Repairs

Perform the following steps to verify repairs:‪

  1. Reinstall all connectors.
  2. Test drive vehicle to see if the problem is corrected.
    1. If engine brakes operate correctly, troubleshooting is complete.
    2. If engine brakes do not operate, all system diagnostic checks are complete. Review this section to find the error. Refer to "10.10.1 Engine Brake Inoperative" , or contact Detroit Diesel Technical Service for possible ECM replacement.


DDEC III/IV Single ECM Troubleshooting Guide - 6SE497
Generated on 10-13-2008

Leave a Reply

Your email address will not be published. Required fields are marked *