An old Toyota Prius came to us after being off the road for a considerable amount of time, as well as having a change of ownership as a result of its on-going problems.
With multiple parts thrown at the car, from a new master cylinder to a new ABS unit and a new brake power supply capacitor, we confirmed the customer's complaints of no brakes and multiple lights on the dash.
A full system scan using the Genuine Toyota tool, which is called Techstream, revealed the codes and a direction we needed to go in. Because multiple garages had had a go at this vehicle, we cleared the codes to see what the hard code was, i.e. what code would not clear and come back straight away. We did indeed have a code a C1377 Capacitor.
We looked at the wiring diagram going to the Capacitor and started our testing. With all voltage and earths present and correct, we then load tested all the circuits and found our problem. On pin 8 at the capacitor, we had voltage but no current flow using a simple test light. We confirmed to the customer that they hah a corroded wire somewhere between the fuse box under the bonnet and the capacitor in the boot.
We gave pin 8 an alternative power supply - all codes were cleared and normal service was resumed!