Each month in Diagnose This! we present a real-life service scenario with clues as to what the ultimate diagnosis was. If you think you know the answer, be the first to e-mail [email protected] with the correct response for free Truck Parts & Service merchandise. The answer will be revealed in a future issue of the magazine.
This month’s Diagnose This! is submitted by ASE master technician and owner of Fleet Guardian, Damon Russell.
Vehicle: 2000 Autocar ACL64B
Key components: Cummins N14 engine, Roadranger transmission
Scenario: Vehicle has a Gus Pech drill apparatus and rear throttle controls. The throttle control uses an SAE J1922 interface and the rear control is a vernier-style potentiometer. The problem is an intermittent runaway engine and/or an idle-only condition. The J1922 throttle interface has limited self-diagnostic ability via an LED display on the control unit.
Clues:
