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2003 Mack R688s E7 350 8LL
in Electrical, Electronics and Lighting
Posted
I just bought the truck with this issue it has code 4-1 speed sensor engine is derated low power I replace the speed sensor 1 turn back out after bottoming out as it says the old one was plastic had a lot of oil and grease on it so the ring is not loose I repaired the oil leak and went ahead to test drive and still speedometer not working and still no power I don't have a wiring diagram to trace the problem.