I have an 03 6MT coupe and im having issues with starting. Sometimes it starts right up and other times it takes 10 minutes of trying. The alternator, starter and battery are good, and i just replaced the clutch position sensor and starter relay. Whenever i try to start it, theres no clicking or anything, just sounds like the battery is dead but itested it and everything lights up. It also occasionally dies while running, the abs slip and vdc off lights come on and it just bogs down and dies. Sometimes when i pull the windshield wipers, those lights come on and it dies. Im not sure if this can be an issued cause by the ignition switch or a bad ground because it has codes U1001 and P1212 but ive brought it to a mechanic and he said those codes could just be popping up and not actually the issue. If anyone can provide me direction as to where to look, IPDM, ignition switch, or anything else that would be amazing. It has become a chore to drive thing thing now. Thanks! I can provide a video if needed.

 

That sounds EXACTLY like a dying battery, how exactly did they test it? Did they wheel out a load bank test cart (about half the size of a shopping cart) and test it with the engine off?

If they just used a multimeter then there's no way they could tell you the actual condition of the battery.

However since it also dies for random reasons while running it MIGHT be the crank sensor. On your long start problems does the tachometer move at all? It SHOULD move a little when trying to start the engine.

I would start by disconnecting the battery and thoroughly cleaning up the lugs and battery terminals to make sure it's all clean and tight.

Also check for any water damage on your BCM, ECM, and IPDM. Especially if these things happen shortly after it rains, the cowl drains are notorious for plugging up and then the water just cascades off onto the IPDM. Since it's also affecting the windshield wiper circuit (motor is in the same cowl) I would definitely be searching there as well.