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Discussion Starter · #1 ·
Truck worked yesterday and parked, failed to start this morning.
Throwing code 42- SRS sensor. Checked sensor and wiring ok. Checked Timing sensor and wiring ok. Power to ECM ok, tried another good ecm, still fail to start. Checked gears for rotation ok.

Need help, what else do I check for.

Thanks
 

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Discussion Starter · #4 · (Edited)
I am told that low enginge cranking can trigger this code. I have used new battries and in my opinion cranking speed is good.
 

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You need 195 RPM and an SRS signal to start, If you can get a reader, it will have a section for SRS and while cranking it must go to yes, and the speed must be above 195.
Some codes set to 255 counts and the engine will not start untill they are fixed. Coolant level is the most popular one for that.
I have changed very few of those sensors, be sure the wiring has not been damaged. and do not understand why you would change parts by the ripping and tearing method? That gets expensive, and cures nothing.
 

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Discussion Starter · #6 ·
You need 195 RPM and an SRS signal to start, If you can get a reader, it will have a section for SRS and while cranking it must go to yes, and the speed must be above 195.
Some codes set to 255 counts and the engine will not start untill they are fixed. Coolant level is the most popular one for that.
I have changed very few of those sensors, be sure the wiring has not been damaged. and do not understand why you would change parts by the ripping and tearing method? That gets expensive, and cures nothing.
What do you mean by 255 counts John, and how do I fix that.

Thanks
 

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He is talking about the nunber of time a certain code has gone active. To repair you find the problem causing the code and fix and delete the old codes.How ever i have seen many ecm with that many codes set in it with out any problem when the code is not active.A active code can derate a engine and then when the code goes inactive the code is stored for future info but engine perform ok untill the code goes active again.He is saying he has seen them stay derated when they get 255 times recorded.The ecm stops counting active codes at 255 counts.
 

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Discussion Starter · #8 ·
Finally got it started, changed both SRS and TRS sensors

ANOTHER ENGINE

My Friend just purchased a used engine Series 60 DDEC 2 but the engine that he removed is a DDEC 3. He is using his DDEC 3 ECM and trying to start but it is not starting.
The reason why he is using the DDEC 3 ECM is because the Truck harness does not correspond to the DDEC 2 ECM.

Any ideas what may be wrong here.
 

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1,138 Posts
Finally got it started, changed both SRS and TRS sensors

ANOTHER ENGINE

My Friend just purchased a used engine Series 60 DDEC 2 but the engine that he removed is a DDEC 3. He is using his DDEC 3 ECM and trying to start but it is not starting.
The reason why he is using the DDEC 3 ECM is because the Truck harness does not correspond to the DDEC 2 ECM.

Any ideas what may be wrong here.
The wiring to the truck and some of the switchs need to be rewired and some switchs have to be replaced to change from a DDEC 2 to 3 or a 3 to a 2.Dont try to change ecms cause the bull gear if different on a 2 than a 3. The timing pin is in different local.
 

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Discussion Starter · #10 ·
The wiring to the truck and some of the switchs need to be rewired and some switchs have to be replaced to change from a DDEC 2 to 3 or a 3 to a 2.Dont try to change ecms cause the bull gear if different on a 2 than a 3. The timing pin is in different local.
theakerstwo
Are you saying that DDEC 3 ECM cannot work on the DDEC 2 Engine because the bull gear is different.
 

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Discussion Starter · #12 ·
Yes i am. You can not use a DDEC 3 ecm on a
ddec 2 engine with out some more changes like the program is different plus the engine harness and the ecm to truck wiring is some different.
Thanks Friend and a HAPPY NEW YEAR 2012.
 

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OK I have found wiring schematic for DDEC2, so I think he will have to do the changes and use the DDEC2 ECM.
And also check all of your dash switch to see if the all work the way they should. I have did one before and i think it was the cruz switchs that were backwards.
 

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I am also experiencing low rpms when trying to start. I have tried everything I can think of either want crank it. It's a 93 freightliner cab over with a ddec2. Checked all batteries I have checked starter I have checked all connections and still nothing. What am I missing?
 
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