intermittent power lost to ecm

There is a wire from battery to ECM with fuse. Not sure about FLD, I work for Volvo dealer, but... seems to me there is thin wire from battery box to ECM. Check it!

 

have you checed voltage on Pin 26 (ign.) on C-connector?

May be you have faulty ign. switch

 

do you know what relay is clicking when this happens?

 

I had a similair prob. not exactly like yours. mine would cut out going down the road & then pick right back up as if someone was disconnecting & immed reconnecting the power. after weeks of frustration & not 1 person could tell me what it was other than try this ,try that, & spending time & money to no avail. problem only got solved when I replaced all battery jumper cables & main hot & ground & cleaned the ground on the frame & starter & hot on the starter. what got me to do this was, after checking & cleaning all connection, I figured o.k. all cables are good, cleaned & tight. then I looked closer at main hot & ground. I sawa lil green on wire beneath thee heavy rubber coating. I took a razor & cur back the rubber on both main cable ends & it was corroted bad. everything looked real good until the rubber was pulled back. looking back, I attributed that to the new type of salt used up north. it is in a liquid form. just like water. it get into & under everything. so after replacing all battery cables. the problem never came back. I too had srs & trs sensors put in plus other try this b.s. process of elimination mechanics. I have no idea if this info will help you, I hope it will be helpful to someone. when ever you get it fixed, post here so we can learn what it was & how to fix. good luck.

 

I do not think EPS is bad! there are two coils in EPS and engine keeps runnimg with one bad coil, but with faulty code. so I sugest wiring, connectors issues. ore may be ign. switch

 

Mine did this for a few months before it finally bit the big biscuit. It showed no error codes when checked.

 

I had one time that was similar. Turned out it was the connection at the battery. The crimp was on it's last leg under the insulator boot. You know how you bend a piece of metal back and forth until it breaks. Well that crimp was right before the breaking point. I guess from vibration and changing batteries over a long time. I pulled on it and it snapped in two. Give that a wiggle check.

Either that or what heavyhauler says... it's a connection/conductivity problem. When a truck doesn't run, if it's not a fuel issue, it is usually that ECM hot wire.

Pablo said a faulty ignition switch. That is a possibilty. They have little mini copper contacts inside. One can break and it can move around, make contact, don't make contact.

But I put my money on the battery connection. Cut the wire back to clean wire and put a new crimp on.

 

Gentelmen! Put money in DVOM first! and locate the problem.

You think like dealers, part changers...

they change parts for two reasons: they do not want to think, to change part is easier and they change parts till sovle problem; they sell all parts to you and get more $$$$.