JC47 - Check For C4 Low - ICM and Coil Disconnected - KOEO

- Key Off.

- Disconnect ICM from ICM tee, leave EI diagnostic harness connected to vehicle harness connector.

- DVOM on 40 volt DC scale.

- Key On, Engine Off.

- Measure voltage between (+)J18 (LC4C) and (-)J7 (B-) at breakout box.

- Is DC voltage reading less than 0.5 volts?

YES -- REPLACE ICM. C4 is shorted high. REMOVE all test equipment. RECONNECT all components. Clear continuous memory. Clearing Diagnostic Trouble Codes

Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes

NO -- CHECK connectors, SERVICE or REPLACE harness. C4 is shorted high. REMOVE all test equipment. RECONNECT all components. Clear continuous memory. Clearing Diagnostic Trouble Codes

Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes