Cadillac P1660: Cooling Fan Relay Control Circuit Malfunction

What Does The Cadillac P1660 Code Mean?

Engine started, engine runtime over 10 seconds in closed loop, system voltage over 10.0v, and the PCM detected an unexpected “low” voltage condition on the Cooling Fan Relay control circuit for 2 seconds during the CCM test.

What Are The Potential Causes Of The Cadillac P1660 Code?

Below are some potential causes of this DTC:

• Cooling fan relay control circuit is open or shorted to ground
• Cooling fan relay control circuit is shorted to system power
• Cooling fan relay power circuit is open (check CLNC FAN fuse)
• Cooling fan relay is damaged or has failed
• PCM has failed

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> WORKPRO 582-piece Crimp Terminals, Wire Connectors, Heat Shrink Tube, Electrical Repair Kit
>>> GM Genuine Parts 12633238 Engine Control Module

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Reference Sources

GM, 2013, Service Bullettin – Prior To Any Circuit Testing.