No crank no start, it has been sitting few months?

Tiny
BAYNH
  • MEMBER
  • 2011 MAZDA CX-9
  • 3.7L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 170,000 MILES
Not getting ground signal from PCM to starter relay signal side, have power on load side, wiring diagram shows PCM sends ground and power to starter relay signal side. Only getting power when in crank position. Will crank when put test light to y/gr wire at PCM hooked to battery ground. Also, no comm at dlc.
Wednesday, June 25th, 2025 AT 4:03 PM

2 Replies

Tiny
BAYNH
  • MEMBER
  • 6 POSTS
Cars been sitting few months due to this issue, not much info on it, besides starter has been replaced, also extra PCM in back seat. Also, prndl doesn't light up at cluster or at shifter. Checked 5v ref at MAF that's good, disconnected batt negative checked can at dlc pin 6 and 14 only had 8.8. Disconnected connector 3 at BCM then changed to 120ohms. Want to make sure I didn't miss anything simple before replacing PCM or BCM.
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Wednesday, June 25th, 2025 AT 4:13 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
With the systems on I would check for power and the meter fuse on the right side of the dash, also check the "engine" and "Room" fuse at the left rear of the engine compartment. This guide can help:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

The room fuse runs the BCM which supplies data to the data link connector. The fact that the prndl doesn't light up, it can be a bad TCM. This is going to take some testing, powers and grounds, we should try to get the data link connector working to help us. Please go over this video:

https://www.youtube.com/watch?v=6Tlg3JmgNSQ

Please go over these guides and get back to us.
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Thursday, June 26th, 2025 AT 10:24 AM

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