Hi, my Volvo S40 T5 AWD is having starter issues. When I go to start, it doesnt stay engaged. Sometimes it will crank normally. Most time not. The starter seems weak sometimes. I just replaced the starter and am having the same exact issue. I checked the relay and it is good. I also just replaced the battery so its good Anyone have any ideas?

 

The ignition switch itself has been known to wear out. I replaced mine on my 2005 due to an intermittent no crank condition and that resolved it for me. If you replace it you do not need any programming to match anything to the ECM. It's plug and play. It's a PITA to actually R&R though. Trying to get tools into small tight spaces just cuts your hands up. VIDA actually recommends removing the entire dash to get to it. I just cussed allot and cut a few plastic pieces that were in the way. Shadetree style.

 

also check the battery cables - and look for any signs of them heating up (bad connections => creates resistance => creates heat). You may also try wiggling the key when its acting up to see if that changes anything in the ignition switch).