no start or pcm communication
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1st Gear
Joined: Apr 2026
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no start or pcm communication
I have a 2000 F250 SD 73l. So I have no pcm communication and no start, all of my fuses are good .
Pin 7 (K‑line) = 4 volts → PCM half‑awake
Pin 10 (5V ref) = 5 volts → reference circuit alive
Pin 16 (battery) = 13 volts → DLC power good
WTS light comes onThis immediately rules out:
Pin 7 (K‑line) = 4 volts → PCM half‑awake
Pin 10 (5V ref) = 5 volts → reference circuit alive
Pin 16 (battery) = 13 volts → DLC power good
WTS light comes onThis immediately rules out:
- A completely dead PCM
- A totally failed PCM power relay
- Blown fuse 30 (fuel bowl heater short)
- Blown fuse 22 (PCM power)
Lead Driver
Joined: Jun 2004
Posts: 6,354
Likes: 592
From: Amarillo, TEXAS!
Do you have good ground on pins 4 and 5? Have you checked all power and ground pins with an incandescent test light to make sure they can carry a current load? If those are good, I'd start checking all power and ground circuits at the PCM connector the same way. Then before condemning the PCM, I'd check them all over again, along with any VREF outputs from the PCM.
But yeah, kind of need to be sure the PCM is online and functional before going after anything no-start related . . .
But yeah, kind of need to be sure the PCM is online and functional before going after anything no-start related . . .
Last edited by Pikachu; Apr 4, 2026 at 08:42 AM.
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