DDEC III/IV Single ECM Troubleshooting – Section 10.12 Miscellaneous Digital Output Fault

Section 10.12
Miscellaneous Digital Output Fault

This section is designed to diagnose an output fault (feature not functioning). Since all outputs operate in the same manner, this troubleshooting section can be used regardless of the function assigned.‪

Section 10.12.1
DDEC ECM

The DDEC ECM has six available digital output cavities. Three are located at the engine harness connector and three at the vehicle harness connector. Output functions (features) are assigned (programmed with the programming station) to any available cavity. The ECM switches the cavity to battery (-) to allow the function to activate. Some output activation is dependent on other parameters being met. (e.g. minimum, r/min, etc.) Perform the following steps to check the DDR for codes. Available output cavities are listed in Table "Output Cavities" .‪

Additional outputs could be added at a later date. Available functions are listed in Table "Available Output Functions" .‪

Output Cavities ‪	Output Cavities ‪
VIH‪	ESH‪
A1 #988‪	W3 #563‪
A2 #555‪	X3 #564‪
F3 #499‪	Y3 #565‪

Functions ‪	Functions ‪	Functions ‪
No Function‪	Fan Control #2‪	Turbo Recirc Valve‪
Low DDEC Volt‪	Deceleration Light‪	Optimized Idle Active‪
RPM Sync Active‪	Engine Brake Active‪	Low Range Solenoid (ESS)‪
PSG Active Light‪	VSG Active Indication‪	High Range Solenoid (ESS)‪
Vehicle Power Down‪	Oil Pressure Low Light‪	Shift Solenoid (Top2)‪
Starter Lockout‪	Oil Temp High Light‪	Shift Lockout (Top2)‪
Ext Brake Enable‪	Coolant Temp High Light‪	Gas Throttle Actuator‪
Trans Retarder Enable‪	Air Comp Solenoid‪	Fuel Supply Solenoid‪
Coolant Level Low Light‪	Crankcase Pressure High‪	KD Brake Solenoid‪
Cruise Active Light‪	Coolant Pressure Low‪	-‪
Fan Control #1‪	Ether Start‪	-‪

Section 10.12.2
Activate Output

Perform the following steps to attempt activation to troubleshoot an output fault.‪

1. Turn ignition ON.
2. Plug in DDR. Select ACTIVATE OUTPUTS.
3. Activate output associated with the fault.

   Note: Service any other codes first.

   1. If the feature operates (e.g. light illuminates or solenoid activates, etc.) review the Application and Installation manual for the operation of the designated feature. Operation is dependent on other parameters. Refer to "10.12.6 Verify Repairs" .
   2. If the feature does not operate or cannot be activated, refer to "10.12.3 Check for Open" .

Section 10.12.3
Check for Open

Perform the following steps to check for open circuit:‪

1. Turn ignition OFF.
2. Locate device end of output wire (e.g. light) and disconnect wire.
3. Turn ignition ON.
4. Measure resistance between the disconnected wire and battery (-).
   1. If the measured resistance is less than 46,000-48,000 Ω, refer to "10.12.4 Check for Voltage" .
   2. If the measured resistance is greater than 48,000 Ω, the wire is open. Refer to "10.12.6 Verify Repairs" .

Section 10.12.4
Check for Voltage

Perform the following steps to check the voltage:‪

1. Measure voltage between the disconnected wire and a good ground.
   1. If voltage measurement is less than 2 volts, refer to "10.12.5 Check for Resistance" .
   2. If voltage measurement is greater than 2 volts, the output is shorted to a voltage source. Replace the wire and refer to "10.12.6 Verify Repairs" .

Section 10.12.5
Check for Resistance

Perform the following steps to check for resistance at the ECM:‪

1. Turn ignition OFF.
2. Disconnect 30-pin connector that houses the wire/function you are checking (e.g. X3-engine harness connector, A1-VIH).
3. Measure resistance between the pin on the ECM and the ECM case.
   1. If the measured resistance is 46,000 to 48,000 Ω, contact the OEM or the hardware of the supplier of the features. For further troubleshooting, all output wiring and ECM operation appear to be operating correctly.
   2. If greater than 48,000 Ω, try a test ECM. Refer to "10.12.6 Verify Repairs" .

Section 10.12.6
Verify Repairs

Perform the following steps to verify repairs.‪

1. Connect all connectors.
2. Test the vehicle and attempt to operate the feature.
   1. If the feature works correctly, troubleshooting is complete.
   2. If the feature still does not work correctly, review this section to find the error. Refer to "10.12.2 Activate Output" .