HELP! start error after cleaning ground connections at firewall

camputee

Member
My 2004 T1N is new to me and this is my first one. I've been trying to track down the reason for a U0423 code and LHM turbo underboost. Today I decided to make sure the ground connections were making good contact, so I cleaned the negative ground connections at the firewall and both negative and positive battery terminals. I was proud of the job I did until I tried starting it. My cluster lights up like normal but it shows start error after it cycles through the light sequence. So I plugged in my innova scanner and it shows a laundry list of transmission codes P0500 generic speed sensor A, U0122 lost communication with vehicle dynamics control module, U0101 generic lost communication with TCM. The thing is it never has had any of these codes nor has it ever shifted incorrectly. The other thing is, I had the battery disconnected for about an hour while I cleaned the connections, so there shouldn't be any codes right? I checked the numbers 16,17,and 18 fuses and they are all good, but I'm not getting power to either side of the number 16 fuse. The only thing I have going for me is I found a Sprinter that a guy was parting out and bought the fuse block, ecm, cluster, ignition, Cruise control stick and some other goodies. WHAT DO I DO? I was planning on going to southern Cal. tomorrow to pick up a two seat bench for it but maybe I should be parting this thing out.

:yell:
 

Midwestdrifter

Engineer In Residence
Did you disturb the main harness by the firewall?

Did you disturb the power distribution block (battery positive)?

What is the battery voltage when sitting? What is the voltage with the ignition on? Turn the headlights on, does the voltage drop below 11.8-12v?


The codes for communication mean one of two things (assuming the codes are current). Either your CANbus wires are damaged/shorted, or the modules in question are not getting power.


I would go back through and confirm everything you did, double check connections etc. Make sure your battery is up to snuff, it needs to be above 12.4 after sitting with no load for an hour.

Removing the battery power does not clear any codes. They are stored in the modules until cleared. Cycling the ignition power on/off will sometimes switch codes from active/current to stored, but that is it.
 

autostaretx

Erratic Member
Rule One: always suspect "Whatever you did last"

It's quite possible that the battery's ground cable is internally frayed, or at least one of the ground points you cleaned isn't really making good contact throughout the stack.

Disconnecting the battery should *only* cause the radio to forget its "code". Nothing else should be bothered.
(my 2005 didn't care that i spent an hour changing the battery, for example)

Your multitude of codes screams of too-low voltage. Check the 12v socket on the dash with a voltmeter after turning on the key.

--dick
 

autostaretx

Erratic Member
Are you speaking of Fuse 16 on Fuse Block One (under the steering wheel), or on the driver's seat pedestal?

If it's Block One ... here's the list of fuse functions:

FuseBlock1.png

Referring to the service manual (you can download a 2004 manual from http://diysprinter.co.uk/reference ) Block One's Fuses 16 and 17 are tied together on the "hot" end. (page 8W-10-12 Section 8W, subsection 10, page 12)... but they are powered by a relay ... the "engine control relay" that is the middle one of the three hanging off the bottom of fuse block one.

FuseBlock1relays.jpg

So check the relay's seating (And that you didn't mix up the relays)

--dick
 

camputee

Member
Did you disturb the main harness by the firewall?

Did you disturb the power distribution block (battery positive)?

What is the battery voltage when sitting? What is the voltage with the ignition on? Turn the headlights on, does the voltage drop below 11.8-12v?


The codes for communication mean one of two things (assuming the codes are current). Either your CANbus wires are damaged/shorted, or the modules in question are not getting power.


I would go back through and confirm everything you did, double check connections etc. Make sure your battery is up to snuff, it needs to be above 12.4 after sitting with no load for an hour.

Removing the battery power does not clear any codes. They are stored in the modules until cleared. Cycling the ignition power on/off will sometimes switch codes from active/current to stored, but that is it.
No I just removed the ground bolt and scuffed up the connectors and the firewall.

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camputee

Member
Rule One: always suspect "Whatever you did last"

It's quite possible that the battery's ground cable is internally frayed, or at least one of the ground points you cleaned isn't really making good contact throughout the stack.

Disconnecting the battery should *only* cause the radio to forget its "code". Nothing else should be bothered.
(my 2005 didn't care that i spent an hour changing the battery, for example)

Your multitude of codes screams of too-low voltage. Check the 12v socket on the dash with a voltmeter after turning on the key.

--dick
Thanks Dick, I will do that first thing in the morning.

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Midwestdrifter

Engineer In Residence
No I just removed the ground bolt and scuffed up the connectors and the firewall.

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Did you get all the wires back on the stud/bolt? If I remember correctly there are more than one group of wires attached at the battery firewall stud. If one of the wring terminals/wire groups was not put back on the stud, that could cause all kinds of crazy.
 

camputee

Member
Did you disturb the main harness by the firewall?

Did you disturb the power distribution block (battery positive)?

What is the battery voltage when sitting? What is the voltage with the ignition on? Turn the headlights on, does the voltage drop below 11.8-12v?


The codes for communication mean one of two things (assuming the codes are current). Either your CANbus wires are damaged/shorted, or the modules in question are not getting power.


I would go back through and confirm everything you did, double check connections etc. Make sure your battery is up to snuff, it needs to be above 12.4 after sitting with no load for an hour.

Removing the battery power does not clear any codes. They are stored in the modules until cleared. Cycling the ignition power on/off will sometimes switch codes from active/current to stored, but that is it.
Okay I will check it out tomorrow.

Thanks Midwestdrifter

Sent from my Pixel 2 XL using Tapatalk
 

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