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4L80E no overdrive
- Thread starter A Aron
- Start date
MrMarty51
Well-Known Member
Hello A A Ron, I dont have a clue as to where to start with the diagnosis, but, welcome to the forum.
Rockabillyrat
SlIgHtLy StUpId.
The PCM uses input from the speed sensors, engine rpm, throttle position and temperature sensors all to control overdrive. Get a scanner on it, check for codes, check your sensor data and go from there. I feel like a broken record on this site lately.
Rockabillyrat
SlIgHtLy StUpId.
The DLC has a fused power source. On the trucks it normally shares the cigarette lighter fuse or the aux power fuse for a power source. I dont remember on the RVs if it's the same. Check all your fuses and go from there
In a pinch I've jumped power to the DLC.
In a pinch I've jumped power to the DLC.
Last edited:
- Staff
- #7
Gotta scan it to see what's up. Most likely it's a temp sensor issue as overdrive is inhibited until the engine and trans warm up.
Hard to get it scanned when it seems no one has an OBD 1.5
- Staff
- #10
OBD1.5 was only in late 94 and 95 in S10's, Camaro's, and 1 or 2 others. A 97 by federal law is obd2.
Will L.
Well-Known Member
Being a motorhome it would surprise me. 96 was D day for obd2, but there were a lot of medium duty trucks, step vans, and motorhomes that got waivers up to 99. When I was Mac guy, I almost bought a 99 chevy step van that was obd1. They had to pay fines that went up dramatically after 2,000 units produced.
That’s why GM jumped the gun so much on the ds4 on 6.5s- they knew it would kill them. I really wish they had waited a couple more years before rolling it out.
That’s why GM jumped the gun so much on the ds4 on 6.5s- they knew it would kill them. I really wish they had waited a couple more years before rolling it out.