A 2004 Freightliner Columbia with a Detroit 14L engine recently developed issues after running smoothly for two weeks. The initial problem, a PID 354 code, was resolved by replacing a faulty Relative Humidity sensor. However, a new problem arose, indicated by a SID 060 code, pointing to a potential issue with the VPOD (Vehicle Power Distribution Module).
The SID 060 code signifies a PMW (Pulse Width Modulation) #4 open circuit, often related to the VPOD harness. Prior to the SID 060 code, the truck exhibited fluctuating turbo noise at idle, with the sound cutting in and out. This was accompanied by seemingly random boost fluctuations without any throttle input. While the truck initially ran fine despite these symptoms, it subsequently experienced significant power loss and a noticeable decrease in turbo noise, even disappearing completely at idle.
Before resorting to Detroit-specific diagnostic software, visual inspection of the VPOD for loose wires and connections is recommended. Given that the Detroit diagnostic manual associates the SID 060 code with an open circuit, replacing the VPOD harness could be a potential solution. Checking all connections and the harness for any signs of damage, such as chafing or exposed wires, is crucial.
Inspecting the PMW #4 circuit itself for continuity using a multimeter can help determine if a break exists within the wiring. Verifying the integrity of the fuses and relays associated with the VPOD and the PMW circuit is also essential. While a laptop with Detroit diagnostic software provides more comprehensive insights, these preliminary checks can be performed without specialized equipment. If these initial inspections don’t reveal the problem, further diagnostics with Detroit software will be necessary to pinpoint the exact location of the open circuit within the PMW #4 circuit and determine the appropriate course of action.
