28/01/2026
TD5 ECU with no fuel pump drive, this is one of 2 quad driver chips, the one in the photo drives the fuel pump relay, and also the ABS pump, auxiliary fan and RPM out signal. The other identical chip next to it drives the glow plug relay, glow plug light, A.C. relay and MiL light. These chips take their inputs logic from the ECU processor then output a high power lowside drain that is also monitored and can send fault codes back to the ECU pro via a data bus. These chips in the photo are from a NNN500020 but in the NNN000120 they use different quad driver chips and that’s the main difference between the 2 ECU’s, that’s why if you flash a firmware from the wrong ECU type you get fault codes related to the outputs I mentioned. These chips are obsolete so I had to use one from a donor ECU, but I do have some on order. I replace these by using hot air.