When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hey all, usually hang out in 73-79 forum as those are the ones I’m passionate about, but currently drive a 92 F250 351W with E4OD. Previously I have had intermittent problems with hard shifting very rarely, usually short shifting 3rd gear, but lately the torque converter quit locking up. It will try once most times I drive it, but kicks right out again. But since this has started it shifts through all gears as it should, staying in 3rd longer. There is no slippage or other weird behavior. Pulled the codes and got 629 - torque converter circuit failure. So I’m hopeful it’s just an electrical problem. Can anyone point me where to start looking for a problem? I’ve heard about problems with mlps but don’t see how this would affect tq lockup. I’ve heard of bad ecm causing weird problems. Just don’t want to throw money at parts without troubleshooting the problem. Thanks.
That code can only set when there is an electrical circuit problem between the PCM and the torque converter clutch solenoid. The MLPS has nothing to do with this.
It usually means there is a wiring problem between the PCM and the torque converter clutch solenoid, though a bad torque converter clutch solenoid can set that code, too. Very rarely a bad PCM can also be the cause.
Disconnect the PCM and the trans and electrically check the wires between the two connectors. Probe the backside of the connectors, NEVER probe the ends that make the connections. That spreads the pins and creates new problems to go along with the problem you're trying to fix. Inspecting the connections doesn't hurt, but only finds the most obvious problems.