DDEC III/IV Single ECM Troubleshooting – Section 10.15 Transmission Interface Fault

Section 10.15
Transmission Interface Fault

Numerous transmissions utilize the DDEC ECM to receive signals that are used to determine shift points, and/or other information.‪

Section 10.15.1
Transmission Fault

Transmissions that currently utilize data links:‪

• J1587 - Allison World Transmissions
• J1939 Eaton, Allison
• J1922 Ceemat
• Advanced Interface
  • ESS ™, Rockwell - Refer to ESS Troubleshooting Manual
  • Top2, Eaton - Refer to MISC Output Troubleshooting
• PWM Signal Type - DDEC provides a PWM signal that is used by the transmission or its components

Section 10.15.2
Verify Transmission Type

Perform the following steps to check the transmission type.‪

1. Turn ignition ON.
2. Plug in DDR.
3. Check transmission origination.
   1. If a manual transmission, Allison hydraulic, Allison Electronic, Voith, ZF, refer to "10.15.3 Review PWM #1 Signal" .
   2. If a J1939/autoshift, Allison WT, Rockwell RXX-X, refer to the troubleshooting manual of the transmission manufacturer to troubleshoot the fault.
   3. If the transmission type does not match the transmission correctly, reprogram and refer to "10.15.4 Verify Repairs" .

Section 10.15.3
Review PWM #1 Signal

Perform the following steps to check the DDR for codes.‪

1. Perform road test with assistant.
2. Plug in DDR.
3. Watch PWM #1 signal.
   1. If the PWM varies with the load changes, and the ECM is programmed as Allison® Electric, Voith or ZF, the signal is normal. Review the wiring or transmission.
   2. If the PWM signal is 0% or 100% when the signal is programmed for Allison Hydraulic with load changes, the program is normal. Review the transmission, wiring or relay. Refer to "10.15.4 Verify Repairs" .

Section 10.15.4
Verify Repairs

Perform the following steps to verify repairs. Start with the Menu Selection. An assistant is needed for the following procedure.‪

1. Perform road test.
   1. If the problem is resolved, troubleshooting is complete.
   2. If the problem still exists, contact the OEM or transmission supplier. The steps that led you here do not indicate a problem with the PWM #2 output or output wire. Verify the correct configuration. Refer to the DDEC Application and Installation manual, 7SA800, for the appropriate engine.