Charge Temperature Switch (CTS) Test

1. No EGR operation with engine warm:
a. Check hose routing and EGR solenoid operation.
b. Remove center connector from CTS and wait 90 seconds.
c. If EGR operation now resumes, replace CTS.
2. EGR operation with engine cold:
a. Check hose routing and EGR solenoid operation.
b. Remove center connector from CTS and check for 10 ohms resistance between center terminal of CTS and ground.
c. If ohmmeter indicates an open circuit, replace CTS.
d. If ohmmeter does not indicate an open circuited CTS, check for open circuit in the CTS to engine ground wire. When replacing CTS switch, do not torque more than 60 inch lbs. Overtorquing will break off the nylon threads in the intake manifold.