Freightliner is a well-known company that makes commercial trucks. To keep track of their vehicles’ health and performance, Freightliner uses high-tech diagnostic tools. Fault codes are built into these monitoring systems to help find problems that might be happening in the truck’s systems. Truck owners, drivers, and workers need to know these fault codes so they can fix problems quickly and make sure the truck runs at its best. In this piece, we will look at a full list of Freightliner fault codes and what they mean.
Freightliner Fault Codes List
MID 128: Engine PID 102: Boost Pressure Sensor Circuit This code means that there is a problem with the boost pressure sensor circuit, which measures the pressure in the intake pipe to control the boost of the turbocharger.
This code means that there is a problem with the engine water temperature sensor circuit, which helps the engine control module keep track of how hot the engine is running.
This code means that there is a problem with the injection pressure control circuit, which will affect how well the fuel injection system works.
2. MID 136 – ABS SID 1 – ABS Wheel Speed Sensor, Steer Axle, Left This code means that there is a problem with the speed sensor for the left front wheel on the steer axle, which affects how the anti-lock brake system works.
SID 4 – ABS Wheel Speed Sensor, Drive Axle, Left This code means that there is a problem with the speed sensor on the left back drive axle wheel, which affects the anti-lock brake system.
SID 6: ABS Wheel Speed Sensor, Right Steer Axle, Front This code means that the right front wheel speed sensor on the steer axle isn’t working properly, which affects the anti-lock brake system.
3. MID 140 – HVAC SID 231 – Ambient Air Temperature Sensor Circuit This code means that there is a problem with the ambient air temperature sensor circuit, which helps the HVAC system adjust based on the temperature outside.
SID 251: HVAC Mode Door Actuator Circuit This number means that there is something wrong with the mode door actuator circuit, which controls the direction of airflow in the HVAC system.
4. MID 144: Instrument Cluster SID 231: Data Link Fault: This code means that there is a problem with the data link between the instrument cluster and other systems in the car, which could make it hard for them to talk to each other.
Check Customer or System Parameters (SID 254)
This code tells the driver or mechanic to check and confirm customer-specific settings or factors in the car’s systems.
5. MID 249: J1939 Control Unit PID 190: Engine Speed Signal This code means that there is a problem with the engine speed signal, which checks the RPM of the engine to make sure it is working properly.
PID 232: Unswitched Battery Voltage This code means that there is a problem with the unswitched battery voltage source, which could affect how well the control unit works.
Engine Fault codes (MID, PID, SID, FMI) FREIGHTLINER
128 Engine # 1 ENGINE ENG
130 automatic transmission – † Trans
136 Anti-lock Brake System (ABS) TRCTR BRK Brake
140 Panel, Left INSTRCLST Instr
142 Panel, Right # 1 INSTRCLST MGMT
172 Diagnostic System DIAGNOSTC DIAG
179 Black Box LOG CMPTR CMPTR
181 Satellite System COMM SAT by Satl
190 ACPU A / C air conditioning
219 Radar VORAD Radar
231 Cellular Communication System COMM CELL Phone
234 Panel, Right # 2 INSTRCLST Instr
General Subsystem Fault Codes (SID for any MIDs) 154 – 248
154 System Diagnostic Code # 4 – † – †
155 System Diagnostic Code # 5 – † – †
219 Burning Indicator † – – †
220 Electrical Connection Tractor / Trailer (ISO 11992) – † – †
221 Supply Voltage for Sensors – † – †
222 Lamp “PROTECT” – † – †
223 Brightness Sensor – † – †
224 Alarm – † – †
225 Yellow Lamp – † – †
226 Transmission Transmission Sensor – † – †
227 Auxiliary Input # 1 – † – †
228 High Pressure Switch HI PRES SWITCH HI Pres SW
229 Kickdown Switch – † – †
230 Idle Confirmation Switch – † – †
231 Circuit SAE J1939 – † – †
232 5 Volt DC Power – † – †
233 Driver # 2 – † – †
234 The mechanism of the “ON” Parking Brake – † – †
235 “Brake” “OFF” mechanism – † – †
236 Power Connection Device – † – †
237 Incineration Connection Device – † – †
238 Diagnostic Lamp – Red – † – †
239 Diagnostic Lamp – Yellow – † – †
240 Memory – † – †
242 Cruise switch “RESUME” – † – †
243 Cruise “SET” switch – † – †
244 Cruise Switch “ENABLE” – † – †
245 Clutch Pedal Switch # 1 – † – †
246 Brake Pedal Switch # 1 – † – †
247 Brake Pedal Switch # 2 – † – †
248 OEM Diagnostic Circuit – † – †
* On March 7, 1997.
If there is no text message, the display area will be blank. Only the SID number will display.
General Subsystem Codes (SID for any MIDs) 249 – 254
249 Chain SAE J1922 SAE J1922 SAE J1922
250 Chain SAE J1708 (J1587) – † – †
251 Power POWER SUPPLY POWER SUPPLY
252 Calibration Module – † – †
253 Memory Calibration – † – †
254 Controller # 1 CONTROLLER Controller
* On March 7, 1997.
If there is no text message, the display area will be blank. Only the SID number will display.
Fault Codes (FMI)
FMI / Description / Text Message
00 Above HIGH
01 Below Low
02 Floating or Wrong Erratic Signal
03 Voltage is higher than normal or short circuit in power Short Hi
04 Voltage below normal or short to ground Short Lo
05 Current below normal or open OPEN
06 Current above normal or short in ground Short
07 Mechanical system does not respond correctly NoRESPONSE
08 Unusual Frequency, Pulse Length, or SIGNAL Period
09 Unusual Update Rate. UPDATE
10 Unusual Rate Rate Change
11 Error not clear Not Known
12 The unit itself does not work correctly. Bad
13 Calibrate incorrectly calibrated.
14 RSRVD Special Instructions
15 Reserved RSRVD
Download More Fault Code List : Download Pdf
These are just a few of the many trouble codes that can show up on the diagnostic system of a Freightliner truck. For accurate diagnosis and troubleshooting, you need to look at the manual for your model or talk to a trained technician. Finding and fixing trouble codes quickly can help keep the car from getting worse and make sure it runs safely and reliably on the road.