1999 V70-XC ETM Issue from Power Side

[El Cheapo]

I'm having ETM-like symptoms (rough idle, limp-home mode, etc), but all the codes point to power issues feeding into the ETM. There are no MAF codes, and I have replaced the main engine management relay. Once it gets sufficient power, the ETM seems to function normally. So, I'm left with a couple of possible options: 1) bad ETM ground connection (which I will check) or 2) something robbing power to the ETM, which needs at least 12.5 volts to function properly.

Has anyone run across a similar problem and is willing to share the sequence of tests used successfully to trace the issue? What's the recommended way to get to and troubleshoot bad connections/wires in the main wiring harness at the fuse box?

Some folks have traced ETM issues to a corroded + battery cable, but mine was replaced within the last two years and still looks clean, both at the fuse box and battery terminal.

Any suggesions or helpful hints would be greatly appreciated. Thanks!

[chuffs]

With meter: touch leads on Ohms, note reading.....disconnect battery leads (when reconnecting-key in pos. 2 connect neg. then positive to avoid SRS light), check from fuse box to positive battery post connector on disconnected cable.. note steady ohms reading and subtract lead resistance (noted while initial touching leads) do the same for battery CABLE negative connector to body ground. (saw the following in a Youtube video) He checked for 12+ ("12.5"volts?) volts to base of ETM relay in eng. compt. fuse box then if input to relay (schematic on side of relay plastic case (mine blue color case) and out put to wire going to TPS check for 12+ ("12.5"volts?) to TPS. There is another decent Youtube on how to use a staple or a "stick-pin" to back-stab the ETM TPS connector while running or operating the ETM butterfly (.5-5 volts in his case--supposedly good). Verify ETM butterfly nut sticking--use specialized cleaner (not cheap subs) clean carefully and manually check for binding...As you stated IF you are correct in stating 12.5 volts necessary, any volt. drops could cause havoc. Good Luck.

[chuffs]

It could be the ETM about to fail, plenty of posts about this in the "Dons ETM" forum section, it is worth removing and cleaning out the ETM then refit it and see if the problem is cured but ETM failure is something that does affect the 99- cars.

Another poster-Mike stated-"As it is now cold are you sure the engine coolant temp sensor is working correctly and also the thermostat, although I wouldn't expect issues with these to cause it to stall out on you.

One recent one I have seen on a non turbo 99 was the wires to the variable cam timing actuator trapped under one of the plastic engine top cover that did cause the car to stall and rough idle so if you have disturbed the top plastic cover recently it might be worth removing it to check for wiring damage"