A fleet of 500 vehicles can generate over 200 fault codes daily. Manually reviewing these codes is time-consuming and can lead to overlooking critical issues. This article outlines 10 common Freightliner Acm Fault Codes classified as “minor,” meaning they likely won’t cause immediate breakdowns. Understanding these codes can save fleet managers valuable time and prevent unnecessary maintenance.
check engine light fault code
Common Minor Freightliner ACM Fault Codes
These codes, analyzed from millions of data points, represent common, less severe issues:
1. SPN 1761: Aftertreatment 1 Diesel Exhaust Fluid Tank Volume Low
Type: Exhaust
This frequent code simply indicates low DEF fluid.
Simple Fix: Refill the DEF tank.
2. SPN 524042: Radar Distance Feature (RDF) Mounting Misaligned
Type: Driver Assist
A slight misalignment of the RDF sensor triggers this code.
Simple Fix: No immediate action required. Address during scheduled maintenance. Inspect for bent or loose hardware.
3. SPN 639: J1939 Network #1 Primary Vehicle Network Communication Loss
Type: Electrical
This code signals lost communication between the Engine Control Module (ECM) and another device.
Simple Fix: Defer to next scheduled maintenance. While performance isn’t affected, a technician should diagnose the communication issue.
4. SPN 520256: Window Lift Motor Thermal Cutoff
Type: Electrical
Overuse or overheating of the window motor triggers this code.
Simple Fix: Cycling the ignition often resets the system. Persistent issues may require motor replacement.
5. SPN 1705: Forward View Imager System Malfunction
Type: Driver Assist
This code indicates a problem with the forward-facing camera system.
Simple Fix: Often requires a software update at a dealership. Drivers should be aware of the system’s potential malfunction.
6. SPN 520289: Mirror Heater Malfunction
Type: Driver Assist
This code signals a problem with the heated mirror system, often weather-related.
Simple Fix: Address during scheduled maintenance or at a dealership.
7. SPN 1231: J1939 Network #2 Communication Loss – Aftertreatment Control Module (ACM)
Type: Electrical
The Motor Control Module (MCM) loses communication with the ACM for more than 5 seconds, potentially due to voltage issues or reprogramming errors.
Simple Fix: If a simple power cycle doesn’t resolve the issue, further diagnosis is needed during the next PM visit.
8. SPN 524127: Forward Road Image Processor Issue
Type: Electrical
This code often indicates a lack of power to the Model Predictive Control (MPC) system, possibly due to an obstruction.
Simple Fix: Check for obstructions to the radar. If the code persists after clearing, have it checked during the next scheduled maintenance.
9. SPN U3001: Control Module Improper Shutdown
Type: Electrical
Low system voltage detected by a control module or sensor. Possible causes include a faulty module, wiring issues, or poor connections.
Simple Fix: Inspect for damaged wiring, connectors, or components.
10. SPN U0001: High-Speed CAN Communication Bus Error
Type: Electrical
Indicates an error within the CAN bus system, which connects the vehicle’s various computers.
Simple Fix: This code can sometimes be intermittent. Clear the code and monitor for recurrence. If it returns, further diagnosis is required.
Leverage Predictive Maintenance for Freightliner ACM Fault Codes
Predictive maintenance software, like Pitstop, can help translate Freightliner ACM fault codes and prioritize maintenance needs, saving time and reducing downtime. Consult a qualified technician for proper diagnosis and repair of any fault codes.
