P1860 Chevrolet -

Question

MY CHEVY TRUCK , A 1998 3500 CREW-CAB 7.4L, AUTO TRANS, AC, 2WD, SRW, KEEPS GIVING ME CODE P1860 ONLY, NO OTHER CODES DETECTED, I HAVE REPLACED THE INTERNAL WIRING HARNESES, AND THE TCC SOLENOID, AND THE IGNITION SWITCH, I HAVE TRIED A 12 VOLT HOT LEAD TO PIN "E" ON THE OUTSIDE OF TRANS MAIN CONNECTOR, AM I MISSING SOMETHING, IS THERE SOMETHING EXTERNAL OR INTERNAL THAT I HAVE MISSED, ANYBODY OUT THERE THAT CAN POINT ME IN THE RIGHT DIRECTION? PLEASE HELP!

THANK YOU,
MARK.

Answer 1

P1860 TCC PMW (pulse modulated width) solenoid circuit electrical

Test to see if the TCC solenoid is working,Applying 12 volt hot is a good test, what about the ECM side , The ECM give the TCC a ground, Test the solenoid again . With the key on engine off apply ground to the TCC control side you should be able to hear the TCC solenoid click. Use this method to find a open circuit,