Code Details
| Display code | Navistar Aware SPN 2850 FMI 5 |
|---|---|
| SPN | 2850 |
| FMI | 5 |
| OEM code | Navistar / International Aware SPN 2850 FMI 5 |
| Manufacturer | Navistar / International |
| System | Aware Vehicle Intelligence / Telematics |
| Component | Cellular antenna — open circuit |
| Source address | Unknown or not applicable |
| Severity | low |
| Review status | ai source checked |
| Source confidence | high |
| Last reviewed | 2026-03-26 |
Plain-English Meaning
The Aware module uses a cellular modem for data transmission to the fleet portal. FMI 5 on the cellular antenna means the modem is active (powered on with the transceiver enabled) but detects an antenna impedance that indicates the antenna is missing or the cable is open. Without an antenna, the cellular modem will have very poor or no transmission capability.
Navistar S08312 maps Navistar Aware SPN 2850 FMI 5 to 1xRTT or AMPS Antenna — current below normal or open circuit at Cellular Antenna connection. The fault sets when the transceiver is on and the cellular antenna is disconnected for more than 5 seconds.
Common Symptoms
- Fleet portal shows vehicle as offline or not reporting
- Telematics data transmission to the fleet server is absent or intermittent
- Remote commands to the Aware module (if any) are not being received
Possible Causes
Possible causes may include the items below. The list is not a parts diagnosis.
- Cellular antenna cable disconnected at the Aware module or at the antenna
- Cellular antenna cable damaged — broken coax conductor causing an open circuit
- Cellular antenna physically missing — removed or fell off due to mounting failure
- Antenna connector not fully seated on the module's antenna port
First Checks
- Locate the cellular antenna — typically a stub antenna or external whip mounted on the cab or sleeper roof.
- Inspect the antenna cable from the antenna to the Aware module for damage, disconnection, or the antenna physically missing.
- Confirm the antenna connector is fully seated on the Aware module's antenna port — these are often SMA or similar RF connectors that can back off if not properly tightened.
- If the cable and connector appear intact, measure continuity of the coax cable from the antenna end to the module end.
Can I Keep Driving?
Severity depends on active status, warning lamps, affected system, and related codes. Stop safely for red stop lamps, brake warnings, oil pressure warnings, high coolant temperature warnings, severe derate, or any abnormal vehicle-control concern.
Related Lookup Pages
Sources
- Navistar Aware Vehicle Intelligence Diagnostic Trouble Codes S08312 Navistar / International Truck Body Builder · oem · accessed 2026-05-05 · confidence high
Source: Navistar / International Truck Body Builder, Navistar Aware Vehicle Intelligence Diagnostic Trouble Codes S08312. This page paraphrases factual fields only and is not a substitute for the original document.
Open source - Navistar Engine Diagnostic Trouble Code Body Builder References Navistar / International Truck Body Builder · oem · accessed 2026-05-05 · confidence medium
Source: Navistar / International Truck Body Builder, Navistar Engine Diagnostic Trouble Code Body Builder References. This page paraphrases factual fields only and is not a substitute for the original document.
Open source
FAQ
Can the Aware module still collect and store data with Navistar Aware SPN 2850 FMI 5 active?
Yes. The Aware module collects and stores data internally regardless of cellular connectivity. With the antenna disconnected, it cannot transmit that data to the fleet portal until the antenna is restored. Data collected during the antenna-out period will typically upload when connectivity is restored.
Is the cellular antenna the same as the GPS antenna?
No. The Aware module has separate antennas for GPS reception and cellular data transmission. A cellular antenna fault does not affect GPS reception, and a GPS antenna fault does not affect cellular transmission. They are independent RF circuits on separate cables.
What type of connector does the cellular antenna typically use on the Navistar Aware module?
Cellular antennas on the Navistar Aware module typically use SMA or SMA-type RF connectors. The specific connector type is defined in the installation documentation for the module generation. SMA connectors require hand-tightening to a defined torque to maintain consistent RF connection.