JoeH Posted December 2, 2023 Share Posted December 2, 2023 On 11/29/2023 at 6:36 PM, mjrays said: Thank you for your help this is my first mack 688s been around truck awhile now picked this up short money was sitting about a year and half guy swears ran fine when parked (company closed up shit just sat ) Inquiring minds want to know how you're making out! 1 Quote Link to comment Share on other sites More sharing options...
mjrays Posted December 9, 2023 Author Share Posted December 9, 2023 OK I finally got back to the truck put a bulb in I'm getting a 4 1 code flashing 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 9, 2023 Share Posted December 9, 2023 V-MAC_Fault_Assignments.pdf 35.61 kB · 1 download.url 4-1 is a VSS code.. the speed sensor on the transmission out put seal housing.. I added a codes list that you can print and save.. Jojo Quote Link to comment Share on other sites More sharing options...
mjrays Posted December 9, 2023 Author Share Posted December 9, 2023 27 minutes ago, Joey Mack said: V-MAC_Fault_Assignments.pdf 35.61 kB · 1 download.url 150 B · 2 downloads 4-1 is a VSS code.. the speed sensor on the transmission out put seal housing.. I added a codes list that you can print and save.. Jojo The sensor on the back of transmission is causing it to run rough Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 9, 2023 Share Posted December 9, 2023 I doubt it.. I think yours is too old to derate for a VSS code.. just because,,, inspect the wires for the sensor, the plug is probably on top of the transmission... not sure what transmission you have, but,, if its a screw-in sensor,, remove it and inspect the end of it.. if its good,, put it back in til it touches then back it our 1 FULL turn, and lock it down... drive it over 7 mph to clear the code,, then recheck your codes.. 1 Quote Link to comment Share on other sites More sharing options...
JoeH Posted December 9, 2023 Share Posted December 9, 2023 Did you do multiple code requests? One request blinks out one code, so after the first code is done blinking, punch the cruise control to blink out the next code. Keep doing this til the codes start repeating. 1 Quote Link to comment Share on other sites More sharing options...
mjrays Posted December 9, 2023 Author Share Posted December 9, 2023 4 minutes ago, JoeH said: Did you do multiple code requests? One request blinks out one code, so after the first code is done blinking, punch the cruise control to blink out the next code. Keep doing this til the codes start repeating. It only gve that code I'll check again I held down cruise set 4 the 1 I pushed it down again same code flashed 1 Quote Link to comment Share on other sites More sharing options...
JoeH Posted December 9, 2023 Share Posted December 9, 2023 Do yourself a long term favor, buy Mack Book part number 8-211, it's a list of all fault codes, plus their possible solutions. Here's page 1 of code 4-1: it shows under Additional Symptoms that reduced power option may be enabled. Quote Link to comment Share on other sites More sharing options...
JoeH Posted December 9, 2023 Share Posted December 9, 2023 Didn't like the first picture, it was a bit blurry. 1 Quote Link to comment Share on other sites More sharing options...
mjrays Posted December 9, 2023 Author Share Posted December 9, 2023 31 minutes ago, JoeH said: Didn't like the first picture, it was a bit blurry. Thanks Quote Link to comment Share on other sites More sharing options...
JoeH Posted December 9, 2023 Share Posted December 9, 2023 If you ever have to do wiring repairs, every wire has a code printed on it that tells where it goes. Example in the wiring diagram for this vss sensor, VJ2-12-1.0 indicates it originates at VECU plug J2, pin 12, and the wire size is 1.0. 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted December 9, 2023 Share Posted December 9, 2023 this posting has my attention now.. I was going to leave it, but I changed my mind... JoeH,, you posted some real good info.. I have that book,, I got it after I went to V-Mac school when I was at a Mack dealership.. I'm glad to see that these books are for sale on line.. I have 3 sets of driveline books.. 2 to sell... but so far know one is interested.. 1 Quote Link to comment Share on other sites More sharing options...
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