Ametek 387 Service Manual page 62

Probable Cause - No data from Engine ECU.

Procedure:

1. Start the vehicle's engine and use the Select button to scroll through the SMC

messages. If DIAG appears, the Interface Module is defective and must be re-

placed. If not, go to the next step.

2. Connect the HDT to the rear of any 2-inch gauge. Usually the last gauge in the

series has an unused connector.

3. Use the HDT to verify data for the suspect gauge is present on the private data

bus.

If data for that gauge is present on the private data bus, remove the

gauge and verify that the gauge scaleplate is correctly installed; if the

scaleplate is correctly installed, replace the defective gauge.

b. If data for that gauge is not present on the private data bus, disconnect

the HDT from the 2-inch gauge and connect it to the diagnostic connec-

tor to see if the Engine ECU is placing data for the gauge on the J1708

data bus.

If data for that gauge is present on the J1708 data bus, replace the Inter-

face Module.

d. If data for that gauge is not present on the J1708 data bus, check the En-

gine ECU according to the manufacturer's diagnostic procedures.

Probable Cause - Interface Module incorrectly programmed.