To recreate the fault I detected on previous occassions, I got the car warmed up and then recreated the necessary conditions called for. The N16/4 Fuel Pump Relay was removed and a jumper wire inserted between its connector sockets 7 and 8...which effectively "hot-wired" the fuel pumps into operation. The engine was restarted and a voltage measurement taken betwen sockets 11 (ground) and 2 (TF Signal) on N16/4's connector. The ISCU remained plugged-in out of necessity, but it and the Fuel Pump Relay share the same TF Signal wire coming from the CIS-E Control Unit. The initial value read was 0.72V. As the engine temp escalated, another measurement read 0.48V. The service manual specified a desired range between 3.5 and 5.0V, so this test failed yet again.

Pressing onward, the next test checks the wiring between the CIS-E and the ISCU. With the engine off, the large cable was disconnected from the CIS-E to expose the connector pins within. Referring to the pin assignments diagram for the CIS-E connector page 20 of 07.3-121, the continuity between the origin of the TF Signal on the CIS-E's cable and the receiving socket at the disconnected ISCU's socket was measured at 0.4 Ohms. This was considered a Pass.



The next subtest checked the short connection between the ISCU and Fuel Pump Relay via the number 2 socket on their respective connectors. Proper continuity was confirmed here as well.