Code
U0448
Generic
U — Network/User
Invalid Data Received From Serial Data Gateway Module B
AI status
Completed
Completed
100%
Causes
- Faulty Serial Data Gateway Module B (hardware or internal firmware)
- Corroded, loose, or damaged connector to SDGM B
- Power or ground problem at the gateway module
- CAN/LIN bus wiring short, open, or high-resistance connection
- Bus termination or wiring impedance fault
- Intermittent module wakeup/failures due to low battery or supply faults
Symptoms
- MIL (check engine light) or network warning lamp illuminated
- Loss or intermittent operation of systems that rely on SDGM B (instrument cluster, body modules, radio, HVAC, telematics, etc.)
- Multiple communication-related U-codes present
- Erratic module behavior or features not responding
- Possible strange messages in scan-tool data or missing data channels
What to check
- Use a scan tool to retrieve U0448 and any related/secondary DTCs and freeze frame data
- Verify battery voltage and charging system (vehicle voltage stable at ~12–14.5 V during testing)
- Visually inspect SDGM B connectors and wiring for corrosion, damage, pin push-out, or moisture
- Check module power(s) and ground(s) for proper voltage and continuity
- Monitor network traffic with a scan tool / CAN bus analyzer to confirm message presence and integrity
- Perform wiggle tests on connectors/wiring while watching DTCs and live data for changes
Signal parameters
- CAN_H idle voltage: approximately 2.5–3.5 V; CAN_L idle: approximately 1.5–2.5 V (verify with scope)
- Differential CAN voltage: near 0 V idle, ~1.5–2.5 V dominant during transmission (vehicle dependent)
- Common bus data rates: 125 kbps, 250 kbps, 500 kbps — verify correct bus speed for the vehicle
- Expected message frequency and IDs for gateway-originated frames (verify against OEM message list)
- Checksum/CRC fields and expected values for gateway messages (failures indicate corrupted frames)
- Message timing: expected response windows in milliseconds (missed/late frames may trigger the code)
Diagnostic algorithm
- Record all active and historic DTCs and freeze frame data with a capable scan tool. Note any other network-related codes.
- Check vehicle voltage (battery and charging) and ensure stable supply. Repair any low-voltage or charging faults first.
- Visually inspect SDGM B connectors, pins, and wiring harness for corrosion, bent pins, damage, or water intrusion; repair as needed.
- Verify module power and ground circuits: measure for correct voltages at the SDGM B connector and check continuity to chassis ground.
- Using a scan tool or CAN analyzer, observe network traffic on the affected bus: confirm gateway messages are present, correct IDs, proper timing, and valid checksums/CRC.
- Use an oscilloscope to check CAN_H and CAN_L waveforms for proper idle voltages, differential amplitude, and absence of noise or reflections. Check bus termination resistance (~60 ohms across H and L for two 120-ohm terminators).
- Perform wiggle tests on wiring and connectors while monitoring live data and DTCs to reproduce the fault and locate intermittent connections.
- If another module is suspected of sending malformed messages, isolate or disconnect that node per manufacturer procedure and re-check traffic and codes.
- Check for manufacturer technical service bulletins (TSBs) or required software updates for SDGM B or related controllers; perform reflash/update if available.
- Clear codes and test drive to verify repair. If fault persists after wiring/power and software check, follow OEM procedures for bench testing or replacement of SDGM B.
- After replacement, program/configure the new gateway per OEM instructions and confirm all network communications and functions are restored.
Likely causes
- Intermittent or poor power/ground at SDGM B
- Damaged or loose connector/wiring to the gateway
- One or more nodes on the network sending malformed frames
- Gateway firmware/software fault
Fault status
Status
Invalid or corrupted data received from Serial Data Gateway Module B. Message format, checksum/CRC, timing, or source is not as expected; network communication integrity compromised.
Repair difficulty: Medium
Diagnostic time: 1.0-4.0 hours
Similar codes
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Code
U0448
HYUNDAI
U — Network/User
Invalid Data Received From Gateway “B”
AI status
Completed
Completed
100%
Causes
- Faulty Serial Data Gateway Module B (hardware or internal firmware)
- Corroded, loose, or damaged connector to SDGM B
- Power or ground problem at the gateway module
- CAN/LIN bus wiring short, open, or high-resistance connection
- Bus termination or wiring impedance fault
- Intermittent module wakeup/failures due to low battery or supply faults
Symptoms
- MIL (check engine light) or network warning lamp illuminated
- Loss or intermittent operation of systems that rely on SDGM B (instrument cluster, body modules, radio, HVAC, telematics, etc.)
- Multiple communication-related U-codes present
- Erratic module behavior or features not responding
- Possible strange messages in scan-tool data or missing data channels
What to check
- Use a scan tool to retrieve U0448 and any related/secondary DTCs and freeze frame data
- Verify battery voltage and charging system (vehicle voltage stable at ~12–14.5 V during testing)
- Visually inspect SDGM B connectors and wiring for corrosion, damage, pin push-out, or moisture
- Check module power(s) and ground(s) for proper voltage and continuity
- Monitor network traffic with a scan tool / CAN bus analyzer to confirm message presence and integrity
- Perform wiggle tests on connectors/wiring while watching DTCs and live data for changes
Signal parameters
- CAN_H idle voltage: approximately 2.5–3.5 V; CAN_L idle: approximately 1.5–2.5 V (verify with scope)
- Differential CAN voltage: near 0 V idle, ~1.5–2.5 V dominant during transmission (vehicle dependent)
- Common bus data rates: 125 kbps, 250 kbps, 500 kbps — verify correct bus speed for the vehicle
- Expected message frequency and IDs for gateway-originated frames (verify against OEM message list)
- Checksum/CRC fields and expected values for gateway messages (failures indicate corrupted frames)
- Message timing: expected response windows in milliseconds (missed/late frames may trigger the code)
Diagnostic algorithm
- Record all active and historic DTCs and freeze frame data with a capable scan tool. Note any other network-related codes.
- Check vehicle voltage (battery and charging) and ensure stable supply. Repair any low-voltage or charging faults first.
- Visually inspect SDGM B connectors, pins, and wiring harness for corrosion, bent pins, damage, or water intrusion; repair as needed.
- Verify module power and ground circuits: measure for correct voltages at the SDGM B connector and check continuity to chassis ground.
- Using a scan tool or CAN analyzer, observe network traffic on the affected bus: confirm gateway messages are present, correct IDs, proper timing, and valid checksums/CRC.
- Use an oscilloscope to check CAN_H and CAN_L waveforms for proper idle voltages, differential amplitude, and absence of noise or reflections. Check bus termination resistance (~60 ohms across H and L for two 120-ohm terminators).
- Perform wiggle tests on wiring and connectors while monitoring live data and DTCs to reproduce the fault and locate intermittent connections.
- If another module is suspected of sending malformed messages, isolate or disconnect that node per manufacturer procedure and re-check traffic and codes.
- Check for manufacturer technical service bulletins (TSBs) or required software updates for SDGM B or related controllers; perform reflash/update if available.
- Clear codes and test drive to verify repair. If fault persists after wiring/power and software check, follow OEM procedures for bench testing or replacement of SDGM B.
- After replacement, program/configure the new gateway per OEM instructions and confirm all network communications and functions are restored.
Likely causes
- Intermittent or poor power/ground at SDGM B
- Damaged or loose connector/wiring to the gateway
- One or more nodes on the network sending malformed frames
- Gateway firmware/software fault
Fault status
Status
Invalid or corrupted data received from Serial Data Gateway Module B. Message format, checksum/CRC, timing, or source is not as expected; network communication integrity compromised.
Repair difficulty: Medium
Diagnostic time: 1.0-4.0 hours
Similar codes
Repair manuals
Manual library for HYUNDAI
371
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