EE4 Checking Wiring Harness (Circuit 421)

^ Disconnect air compressor assembly from vehicle wiring harness.

^ Using an analog ohmmeter, connect one lead to vent solenoid valve vehicle wiring harness connector Circuit 430E and other to a known good chassis ground.

^ Is ohmmeter reading lees than 2 ohms?

YES -- REPLACE air compressor assembly and REPEAT Service Bay Diagnostics. Reading and Clearing Diagnostic Trouble Codes

NO -- SERVICE short in wiring harness Circuit . REPEAT Service Bay Diagnostics. Reading and Clearing Diagnostic Trouble Codes