Code
U1100
HYUNDAI
U — Network/User
High Speed CAN 2 Lost communication (EMS-DCT)
Views:
UK: 13
EN: 25
RU: 14
AI status
Completed
Completed
100%
Causes
- Open or short in CAN bus wiring (CANH/CANL) between EMS and DCT
- Poor or corroded connectors at EMS, DCT, or junction connectors
- Failed CAN transceiver in EMS or DCT module
- Missing or failed bus termination resistor(s)
- Blown fuse or interrupted power/ground to one of the modules
- Module software mismatch or module internal fault
Symptoms
- MIL (Check Engine) and/or transmission warning lamp illuminated
- Loss of engine/transmission data on dash or scan tool
- Transmission locked in limp mode or limited shift functionality
- Poor drivability (stalls, limp-home behavior) if EMS data lost
- Intermittent or no communication with one or more control modules
- Multiple network-related DTCs present in other modules
What to check
- Read all stored and pending DTCs from all modules; note freeze-frame and occurrence frequency
- Visually inspect CAN wiring, harness routing, and connectors for damage, corrosion, or moisture
- Check fuses and power/ground circuits for EMS and DCT
- With ignition ON (engine off), measure CANH and CANL voltages at module connectors
- Measure termination resistance across CANH and CANL with ignition off (expected ~60 Ω)
- Use a scope to check for clean CAN differential signals and to identify noise or missing messages
Signal parameters
- Bus: High Speed CAN 2 (HS-CAN)
- Nominal data rate: typically 500 kbps (verify OEM specification)
- Idle (recessive) voltage: CANH ≈ 2.5 V, CANL ≈ 2.5 V
- Dominant state voltages: CANH ≈ 3.5 V, CANL ≈ 1.5 V (approximate)
- Typical differential voltage when dominant: ≈ 2.0 V
- Termination resistance: ≈ 60 Ω measured across CANH–CANL (two 120 Ω terminators in parallel)
Diagnostic algorithm
- Record all DTCs and freeze-frame data from the EMS, DCT, and other modules. Note if U1100 is current or historic and whether it coincides with other U-codes.
- Perform a visual inspection of CAN connectors and wiring between EMS and DCT (including junctions and splice points). Repair any obvious damage or corrosion.
- Verify power and ground to EMS and DCT (check related fuses and relays). Fix any supply issues before further testing.
- With ignition ON (engine off), measure CANH and CANL voltages at the EMS and DCT connectors. Confirm idle voltages (~2.5 V) and compare both module locations.
- With ignition ON, measure termination resistance across CANH–CANL with connectors disconnected where applicable; expect ≈60 Ω. Replace missing/failed terminators.
- Use an oscilloscope to observe CAN differential waveform while operating system functions or cranking; look for missing frames, dominant stuck states, excessive noise, or reflections.
- Isolate the fault by disconnecting suspected modules (one at a time) and checking if bus communication is restored or if errors move to another module. Do not leave the bus unterminated for extended periods.
- If a specific module is suspected (no responses, incorrect transceiver signals), bench-test or replace the module only after confirming wiring and power/ground are good.
- After repairs, clear codes and perform a road test / system exercise to confirm the U1100 does not return and that communication with EMS and DCT is stable.
- If intermittent, consider harness replacement or routing changes to prevent future damage; update module software to latest calibration if indicated by OEM technical service bulletins.
Likely causes
- Loose or corroded connector at EMS or DCT
- Damaged CANH/CANL harness between EMS and DCT
- Failed CAN transceiver inside DCT or EMS module
- Open/failed ground or supply to one module
- Missing/failed termination resistor causing bus reflections
Fault status
Status
Lost communication on High Speed CAN 2 between EMS and DCT. Modules may be unresponsive or showing intermittent messages; network integrity (wiring, termination, power/ground, transceivers) should be verified.
Repair difficulty: Medium
Diagnostic time: 1.5 - 3.0 hours
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Code
U1100
MITSUBISHI
U — Network/User
Engine CAN timeout
Views:
UK: 14
EN: 26
RU: 19
AI status
Completed
Completed
100%
Causes
- Open or short in CAN bus wiring (CANH/CANL) between EMS and DCT
- Poor or corroded connectors at EMS, DCT, or junction connectors
- Failed CAN transceiver in EMS or DCT module
- Missing or failed bus termination resistor(s)
- Blown fuse or interrupted power/ground to one of the modules
- Module software mismatch or module internal fault
Symptoms
- MIL (Check Engine) and/or transmission warning lamp illuminated
- Loss of engine/transmission data on dash or scan tool
- Transmission locked in limp mode or limited shift functionality
- Poor drivability (stalls, limp-home behavior) if EMS data lost
- Intermittent or no communication with one or more control modules
- Multiple network-related DTCs present in other modules
What to check
- Read all stored and pending DTCs from all modules; note freeze-frame and occurrence frequency
- Visually inspect CAN wiring, harness routing, and connectors for damage, corrosion, or moisture
- Check fuses and power/ground circuits for EMS and DCT
- With ignition ON (engine off), measure CANH and CANL voltages at module connectors
- Measure termination resistance across CANH and CANL with ignition off (expected ~60 Ω)
- Use a scope to check for clean CAN differential signals and to identify noise or missing messages
Signal parameters
- Bus: High Speed CAN 2 (HS-CAN)
- Nominal data rate: typically 500 kbps (verify OEM specification)
- Idle (recessive) voltage: CANH ≈ 2.5 V, CANL ≈ 2.5 V
- Dominant state voltages: CANH ≈ 3.5 V, CANL ≈ 1.5 V (approximate)
- Typical differential voltage when dominant: ≈ 2.0 V
- Termination resistance: ≈ 60 Ω measured across CANH–CANL (two 120 Ω terminators in parallel)
Diagnostic algorithm
- Record all DTCs and freeze-frame data from the EMS, DCT, and other modules. Note if U1100 is current or historic and whether it coincides with other U-codes.
- Perform a visual inspection of CAN connectors and wiring between EMS and DCT (including junctions and splice points). Repair any obvious damage or corrosion.
- Verify power and ground to EMS and DCT (check related fuses and relays). Fix any supply issues before further testing.
- With ignition ON (engine off), measure CANH and CANL voltages at the EMS and DCT connectors. Confirm idle voltages (~2.5 V) and compare both module locations.
- With ignition ON, measure termination resistance across CANH–CANL with connectors disconnected where applicable; expect ≈60 Ω. Replace missing/failed terminators.
- Use an oscilloscope to observe CAN differential waveform while operating system functions or cranking; look for missing frames, dominant stuck states, excessive noise, or reflections.
- Isolate the fault by disconnecting suspected modules (one at a time) and checking if bus communication is restored or if errors move to another module. Do not leave the bus unterminated for extended periods.
- If a specific module is suspected (no responses, incorrect transceiver signals), bench-test or replace the module only after confirming wiring and power/ground are good.
- After repairs, clear codes and perform a road test / system exercise to confirm the U1100 does not return and that communication with EMS and DCT is stable.
- If intermittent, consider harness replacement or routing changes to prevent future damage; update module software to latest calibration if indicated by OEM technical service bulletins.
Likely causes
- Loose or corroded connector at EMS or DCT
- Damaged CANH/CANL harness between EMS and DCT
- Failed CAN transceiver inside DCT or EMS module
- Open/failed ground or supply to one module
- Missing/failed termination resistor causing bus reflections
Fault status
Status
Lost communication on High Speed CAN 2 between EMS and DCT. Modules may be unresponsive or showing intermittent messages; network integrity (wiring, termination, power/ground, transceivers) should be verified.
Repair difficulty: Medium
Diagnostic time: 1.5 - 3.0 hours
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Code
U1100
Other
U — Network/User
SCP (J1850) Invalid or Missing Data for Primary Id
Views:
UK: 25
EN: 40
RU: 21
AI status
Completed
Completed
100%
Causes
- Open or short in CAN bus wiring (CANH/CANL) between EMS and DCT
- Poor or corroded connectors at EMS, DCT, or junction connectors
- Failed CAN transceiver in EMS or DCT module
- Missing or failed bus termination resistor(s)
- Blown fuse or interrupted power/ground to one of the modules
- Module software mismatch or module internal fault
Symptoms
- MIL (Check Engine) and/or transmission warning lamp illuminated
- Loss of engine/transmission data on dash or scan tool
- Transmission locked in limp mode or limited shift functionality
- Poor drivability (stalls, limp-home behavior) if EMS data lost
- Intermittent or no communication with one or more control modules
- Multiple network-related DTCs present in other modules
What to check
- Read all stored and pending DTCs from all modules; note freeze-frame and occurrence frequency
- Visually inspect CAN wiring, harness routing, and connectors for damage, corrosion, or moisture
- Check fuses and power/ground circuits for EMS and DCT
- With ignition ON (engine off), measure CANH and CANL voltages at module connectors
- Measure termination resistance across CANH and CANL with ignition off (expected ~60 Ω)
- Use a scope to check for clean CAN differential signals and to identify noise or missing messages
Signal parameters
- Bus: High Speed CAN 2 (HS-CAN)
- Nominal data rate: typically 500 kbps (verify OEM specification)
- Idle (recessive) voltage: CANH ≈ 2.5 V, CANL ≈ 2.5 V
- Dominant state voltages: CANH ≈ 3.5 V, CANL ≈ 1.5 V (approximate)
- Typical differential voltage when dominant: ≈ 2.0 V
- Termination resistance: ≈ 60 Ω measured across CANH–CANL (two 120 Ω terminators in parallel)
Diagnostic algorithm
- Record all DTCs and freeze-frame data from the EMS, DCT, and other modules. Note if U1100 is current or historic and whether it coincides with other U-codes.
- Perform a visual inspection of CAN connectors and wiring between EMS and DCT (including junctions and splice points). Repair any obvious damage or corrosion.
- Verify power and ground to EMS and DCT (check related fuses and relays). Fix any supply issues before further testing.
- With ignition ON (engine off), measure CANH and CANL voltages at the EMS and DCT connectors. Confirm idle voltages (~2.5 V) and compare both module locations.
- With ignition ON, measure termination resistance across CANH–CANL with connectors disconnected where applicable; expect ≈60 Ω. Replace missing/failed terminators.
- Use an oscilloscope to observe CAN differential waveform while operating system functions or cranking; look for missing frames, dominant stuck states, excessive noise, or reflections.
- Isolate the fault by disconnecting suspected modules (one at a time) and checking if bus communication is restored or if errors move to another module. Do not leave the bus unterminated for extended periods.
- If a specific module is suspected (no responses, incorrect transceiver signals), bench-test or replace the module only after confirming wiring and power/ground are good.
- After repairs, clear codes and perform a road test / system exercise to confirm the U1100 does not return and that communication with EMS and DCT is stable.
- If intermittent, consider harness replacement or routing changes to prevent future damage; update module software to latest calibration if indicated by OEM technical service bulletins.
Likely causes
- Loose or corroded connector at EMS or DCT
- Damaged CANH/CANL harness between EMS and DCT
- Failed CAN transceiver inside DCT or EMS module
- Open/failed ground or supply to one module
- Missing/failed termination resistor causing bus reflections
Fault status
Status
Lost communication on High Speed CAN 2 between EMS and DCT. Modules may be unresponsive or showing intermittent messages; network integrity (wiring, termination, power/ground, transceivers) should be verified.
Repair difficulty: Medium
Diagnostic time: 1.5 - 3.0 hours
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Your experience will help others
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