Crank no start after replacing transmission?

PETE CORBETT

MEMBER
2003 SUBARU OUTBACK
3.0L
6 CYL
4WD
AUTOMATIC
130,000 MILES

I just replaced the transmission in my 2003 LL Bean h6 3.0. Extremely hard to find, so it's a used transmission. Now it cranks but no start and threw 2 codes, ECT and a knock sensor high bank 2 code. Fans run constantly with key on. I replaced the ECT sensor and have the same conditions but it threw an additional crankshaft position sensor code. Does this sound ECU related? Car ran great before transmission replacement. I thought I wouldn't have to have any reprogramming done on this year of car, am I wrong about that? I did a basic reboot, but same problems. Thank You!

Thursday, February 26th, 2026 AT 1:49 PM

2 Replies

KEN L

MASTER CERTIFIED MECHANIC
54,942 POSTS

Most of the time the problem will be that one of the main computer grounds has been left off, can you see any grounds wires that do not have a home? I checked out the wiring diagrams and there is a ground at the right rea of the engine that goes to the knock sensors. Check it out and let me know what you find. Check out the images (below). Ken

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Friday, February 27th, 2026 AT 7:47 AM

PETE CORBETT

MEMBER
3 POSTS

I’m pretty sure these are the grounds that you are talking about. They look good, undisturbed. I am unfamiliar with the dotted loops on the wiring diagram, does that mean the sensors are grounded through their threads? I noticed that each knock sensor only has one wire going to it, while the crank and ect sensors have two.

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