[ImperialCrown]

The PCM does have a hand in providing the relay coil ground in order to actuate the relay contacts to energize the starter solenoid to crank the starter over.
The PCM has to give cranking permission first by being sure that the engine isn't already running and that the transaxle is in Park or Neutral.

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[ImperialCrown]

Yeah, grounding the relay pull coil through the P/N or clutch safety switch was the way it used to be done, but now they have a 'smart' ground method. I also doubt that the PCM (ECM) is at fault. It is the last house on the block when it comes to any diagnosis of this sort anyways. If the PCM is not providing a ground for the relay, it may be because it is being told not to by the P/N safety switch or TCM. A faulty P/N safety switch is rare on a 41TE transaxle, but may have to be checked in the diagnosis if we have to go that far. Following the wiring diagram, check for your 12 volts at the B4 and B5 relay socket terminals. Jumping 12 volts to terminal B1 should crank the engine. I don't think that you will see the 'B' numbers printed anywhere on the plastic in the PDC or on the relay itself. They may be identified like this:


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relay.jpg

B1=87
B2=86
B3=87a (not used)
B4=85
B5=30
When they state 'Normally Open' (N/O) or 'Normally Closed' (N/C), that is the switch state of the relay at rest with no current applied to the actuating coil.