92 Buick Skylark no electricity to compressor-ECM code 26?

I own a 1992 Buick Skylark and hit a pothole on a hill at 45 mph. The service engine soon light went on and my air conditioning won't work. I am getting a trouble code 26 which is either a Quad driver error or a Throttle position sensor short. I bought a new throttle position sensor and still have the service engine soon light. The clutch on the compressor is not engaging when you turn the A/C on. I put a meter on the wires that run into the compressor and I am getting no juice? Any ideas what I can do next? The code 26 does indicate a quad driver fault not a TPS problem. A high voltage reading from the TPS will keep the A/C from working however. Do you have a code 21 also?

The quad drivers control the activation of solenoids such the EGR control, canister purge solenoid, transmission control solenoids, cooling fan relays and some do control A/C function. If the ECM sees a higher or lower voltage than is expected on the controlled circuit due to short or open circuit the computer will set a quad driver code. Unfortunately the ECM uses a quad driver to control many circuits and finding the offending circuit can be difficult. Also there are several different types of quad drivers, some can be permanently damaged if a circuit is shorted while others have a built in protection which will keep the quad driver from operating if there is a problem with any of the controlled devices on that circuit. This means a problem with one controlled device on that quad driver circuit could keep all devices which that quad driver controls from working. The circuits controlled and types of quad drivers vary from year to year and are also dependent on engine size, transmission type, emission control type and what accessories the vehicle is equipped with. Unfortunately I have no information on this at home so I don’t know what circuits are controlled by that quad driver or even if this particular system has different codes for different quad drivers. The problem with the A/C may or may not be related to the quad driver code, it depends on the design of this particular system. Maybe Chris can help out on this.

If this problem occurred after hitting the pot hole something may have been knocked loose or damaged, look for any loose electrical connections or damage that may have been caused.

Have you tried clearing the codes and seeing if any return after driving the car?

Chasing quad driver codes can be very difficult at times even with the proper equipment and information, so if you can’t locate the problem easily you may have to have this checked out by a qualified technician.

Good luck