starter start with dei 528t

just tested the grey/red wire. when car is off, v = 0v. when the car is on, P & N is ~14v

Did you test that right at the IPDM?Kevin Pierson

yes, i tested the wire going into the connector. heres also an interesting observation, i extended all the wires so i would have more room to do some measurements and whatnot. the signal from the cpu is faulty so the relay doesnt energize. the signal from the PDU is fine. once i grounded the one to the cpu of the ipdm, terminal 3 (the middle one on the relay) got power. but heres the twist, the V coming from the TCM is fine @ 12v but when under load, it goes to ~0V.

from the fsm sc page: STARTING SYSTEM PFP:00011 System Description NKS003NI Power is supplied at all times
through 15A fuse (No. 78, located in the IPDM E/R)
to CPU of IPDM E/R,
through 15A fuse (No. 71, located in the IPDM E/R)
to CPU of IPDM E/R. Ground is supplied
to IPDM E/R terminals 38 and 51
from grounds E22 and E43. When the selector lever in the P or N position, power is supplied
from TCM, and through A/T assembly terminal 9
to IPDM E/R terminal 53. And then provided that IPDM E/R receives a starter relay ON signal with CAN communication, starter relay is energized. With the ignition switch in the START position, power is supplied
through IPDM E/R terminal 3
to starter motor terminal 1. The starter motor plunger closes and provides a closed circuit between the battery and starter motor. The starter motor is

so my understanding would be if 12v is coming from the TCM, that would mean the IPDM cpu would be providing the ground?

also, from at-89: 9 GR/R Starter relay Selector lever in “N”, “P” positions. Battery voltage Selector lever in “R”, “D” positions. 0V

Yeah, that is what is sounds like - can you verify this voltage is present with a meter (and the wire unplugged from the IPDM)?Kevin Pierson

i guess i am a bit confused ... there is a wire (GR/R) coming from the AT TCM to the IPDM to E9(IPDM) so disconnect that connector (the E10-F1 junction) and measure the voltage & ground with the ign on switching gears? so your saying i am thinking it backwards, the ipdm cpu should be giving 12v+ and the TCM give ground?

KPierson wrote: Try this: Disconnect the wire going to the TCM. Measure for voltage and for ground on the IPDM side then measure for voltage and for ground on the TCM side.  When working with the TCM side make sure the ignition is on and move the shift lever from P to D and observe any changes. Next, try to start the car with your meter on the IPDM side.  Again, while trying to start the car, measure for both voltage and ground on the IPDM side.  It sounds, to me, like the TCM is supposed to be sending a ground to the IPDM.  Another thing you can try is just straight grounding the IPDM side of the cut wire and seeing if the car will start.

what wire are you referring to when you say cut wire? also, by looking at the fsm, would that help any for you to tell me what to do next? sorry, i am i bit confused...