Electronics International CGR-30P - Manual (Page 58)

Troubleshooting the CGR system can be relatively simple. First the CGR must be powered-up. This requires
only a power and ground connection to the CGR. Next the EDC needs to be powered-up and communicating
with the CGR. Power and ground are supplied to the EDC on two wires and the EDC communicates with the
CGR on one 5V-Serial wire. A "COM" error will be displayed if the EDC is not communicating with the CGR.
The rest of the system is made up of individual functions performing independently of each other. A problem
with a pressure channel will most likely be found in the connection to the transducer, the wire from the trans-
ducer to the EDC or the EDC connection. This same scenario is true for all the functions. Rarely is there any
problems with the EDC or CGR. In some cases the problem can be in the setup programming of the CGR.
7.1 CGR or EDC Problem:
The CGR and EDC require power and ground to operate. The EDC also requires one 5V-Serial wire to com-
municate with the CGR. The EDC also supplies power to the Fuel Flow, Fuel Level, and Pressure Transducers.
If these power wires become shorted, the EDC operation will be affected.
A. Symptom: A. Symptom: A. Symptom: A. Symptom: A. Symptom: The CGR does not power up.
1. Problem: The Power or Ground wire is open or not connected properly.
a) Action: Measure the voltage on the power and ground wires. Ohm the ground wire to
ground. Look for a short.
B. Symptom: B. Symptom: B. Symptom: B. Symptom: B. Symptom: “COM” is displayed for the digital value for most functions. The EDC is not communicat-
ing with the CGR.
1. Problem: One of the EDC external +5 volt power supplies on the Bottom Connector is shorted to
ground.
a) Action: Remove the Bottom Connector. If the COM error goes away, look for a short on
one of the +5 volt wires.
2. Problem: The Power or Ground wire to the EDC is open or not connected properly.
a) Action: Measure the voltage on the appropriate EDC pins. Ohm the Black ground wire to
ground.
3. Problem: The EDC +10 volt or one of the +5 volt supplies on the Top Connector is shorted to
Ground.
a) Action: Measure the +10 volt and +5 volt supplies on the Top Connector. If one of the
voltages is low, use an ohmmeter to find the problem. If all wires ohm properly
(>100 ohm when disconnected from the EDC), the Power or Ground wire to the Top
Connector may be open.
4. Problem: The 5V-Serial wire from the EDC to the CGR may be open.
a) Action: Inspect the wire. Remove the connectors from the EDC and the CGR and check for
continuity.
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