ddec codes

[brmax]

Might have to find the number on them wires at the sensor and or up wire a bit  
Some may go through some other equipment or parts before getting a Detroit jacket    and wearing # 115 at the ecm.
Have any pics there of the tank

Floyd

[blue_goose]

Ground both of the wires going to the sensor.  Check where you hooked up the new sensor. 
Jack

[jmblake]

Well I think I did a real stupid thing tonight, I think maybe I fried my ecm I was tracing the wires back to the ecm and they seemed ok up to the ecm so I unpluged the connector from the ecm and there was some corrosion on the pins so I thought that might be my problem.  Then I did a stupid thing I had a small soft brass wire brush that would fit down in the connector hole and cleaned the pins, put everything back together and nothing, started checking things and found 2 blown fuses, so I replaced them and still nothing I have power in the 5 pin connector and the pink ignition wire in the big connector has power. So did I just fry my computer. Feeling really stupid right now I never even thought that side would have power with the key off. Jason 

[brmax]

Hope not! why not take a look at them fuses around the bus first, say in bat box and then mosey around and look at the breakers in rear jct box, kinda bottom left #6, I think? it is but bottom row left and or check sticker diagram on that cover. If possible using a dvom meter for a continuity check with the sound works pretty good.

[jmblake]

Hope not! why not take a look at them fuses around the bus first, say in bat box and then mosey around and look at the breakers in rear jct box, kinda bottom left #6, I think? it is but bottom row left and or check sticker diagram on that cover. If possible using a dvom meter for a continuity check with the sound works pretty good.

Yeah I hope not, but I did replace 2 fuses and I do have power at ecm just no cel or sel when I turn the key on and when I do try to start it just cranks.
Thanks Jason

[blue_goose]

It sounds like you are not getting ignition power to the ECM.  There is some voltage in that socket for the the sensors if the DC plug was powered.  I don't think shorting it out would kill the ECM.  Ignition is wire 439 at pin B-3.  Take plug out and check to see if you bent any pins and check voltage on B-3 with key on.
Jack

[luvrbus]

Jason,there is a outfit in Cheswick Pa called DCS 417-327-9400 that can check your ECM I think they do have a internal protection device,fwiw DCS has never charged me over $400 to repair a ECM but YMMD   

[jmblake]

Thanks guys, I do some more checking over the weekend, hopefully it's not fried. Jason

[jmblake]

Jack, I have 13.2 volt on wire #439 but for some reason now it has power all the time even with the key off. So I unhooked the plug from the ecm and from the ignition solenoid up front and still have power in #439 Does wire 439 go straight from ecm to the front ignition solenoid or is there something in between like a relay that could be bad, the wire goes into the big harness at the ecm and comes out of the big harness up front but I don't know if it splits off somewhere in the harness there's so many wires coming and going it's hard to tell. Every thing worked up until now. Thanks Jason

[blue_goose]

Cavity
Wire No.
Label
VIH-to-ECM Connector
H-3
115
COOLANT LEVEL

D-2
417
LIMITING SPEED GOVERNOR
B-1
419
CHECK ENGINE LIGHT
B-3
439
IGNITION
E-1
451
DIGITAL INPUT #1
F-3
499
DIGITAL OUTPUT #1
K-1
505
TACHOMETER DRIVE
B-2
509
STOP ENGINE LIGHT
D-1
510
OI THERMOSTAT OR PTO OR EXHAUST BACK PRESSURE SENSOR (COACH ONLY)
H-1
523
DIGITAL INPUT #7
H-2
524
DIGITAL INPUT #8
G-1
528
DIGITAL INPUT #4
J-2
531
DIGITAL INPUT #10
J-1
541
DIGITAL INPUT #9
F-1
542
DIGITAL INPUT #2
G-2
543
DIGITAL INPUT #5
F-2
544
DIGITAL INPUT #3
G-3
545
DIGITAL INPUT #6
A-2
555
DIGITAL OUTPUT #2
E-2
556
VEHICLE SPEED (+)
E-3
557
VEHICLE SPEED (-)
K-2
583
DIGITAL INPUT #11
D-3
749
ESS OR FIRE TRUCK PUMP PRESSURE
C-2
900
J1587 DATA LINK (+)
C-1
901
J1587 DATA LINK (-)
J-3
908
VARIABLE SPEED FAN OR PWM TRANSMISSION OR OI ALARM
A-3
916
SENSOR SUPPLY (5VDC)
C-3
952
SENSOR RETURN
K-3
979
DIGITAL INPUT #12
A-1
988
DIGITAL OUTPUT #3
These are the wires in that plug.  B-3 should turn on and off with the switch.  If it doesn't turn off you won't get the check and stop engine.
Jack

[blue_goose]

There are two things that it goes through.  The kill engine switch in the back and the ignition relay in the back drivers side.
Jack

[jmblake]

Okay thanks I'll check that out tomorrow but that wire has juice all the time for some reason thanks Jason

[jmblake]

Forgot would that wire having juice in it all the time keep it from starting? I could see it not shutting off since that would be keeping power there?

[blue_goose]

I don't know, it shouldn't have power all the time.  Did you check to see if you have a bent pin in the eCm.
Jack

[belfert]

Check that relay.  A few years back I found a bad relay that was causing my electric wipers to not work in intermittent mode.