Code
U1128
HUMMER
U — Network/User
Loss of Communications with IRC
Views:
UK: 14
EN: 20
RU: 24
AI status
Completed
Completed
100%
Causes
- Open, shorted, or corroded wiring between IRC and vehicle network
- Faulty or loose connector at the IRC
- Failed IRC module
- Low battery voltage or intermittent power/ground to the IRC
- CAN bus termination or wiring fault (short to battery or ground)
- Network interference from another module or after-market device
Symptoms
- SRS/airbag warning lamp illuminated
- Scan tool cannot communicate with IRC or shows module not present
- Unable to perform airbag module data read or reprogramming
- Related safety systems disabled or reporting faults
- Occasional or permanent loss of other network messages
What to check
- Record freeze-frame, full DTC list, and active/inactive status with a scan tool
- Verify battery voltage at rest and while cranking (should be ~12.0–14.5 V)
- Inspect fuses and power/ground circuits for the IRC
- Visually inspect IRC connectors and harness for corrosion, looseness, or damage
- Attempt to communicate with the IRC using a capable scan tool
- Check for other U-codes on the network that could indicate broader bus issues
Signal parameters
- Supply voltage to IRC: approximately 11–14.5 V (vehicle battery range)
- Ground continuity: near 0 ohms to chassis ground (typically
- CAN bus idle voltages: CANH ~2.5–3.5 V, CANL ~1.5–2.5 V (dominant state will shift toward ~3.5 V / ~1.5 V)
- CAN differential (dominant) ~1.5–2.5 V when active
- Bus resistance (with network intact/terminators): ~60 Ω total (approx. 120 Ω if single-ended? — verify vehicle specific)
Diagnostic algorithm
- Follow safety procedures for SRS work: consult service manual, disconnect battery and wait the specified time before disconnecting IRC connectors.
- Connect a factory-level or qualified scan tool; record U1128 and any related codes, then attempt to communicate with the IRC.
- Verify battery voltage and check related fuses/power feeds to the IRC. Repair any blown fuses or poor battery connections.
- Inspect IRC connector and wiring for corrosion, bent pins, or physical damage. Repair or replace as needed.
- With ignition ON (battery connected), measure supply voltage and ground at the IRC connector pins. Ensure correct voltages are present.
- Check CAN network: measure CANH/CANL voltages at the IRC connector and at another module. Compare readings and look for open/short conditions.
- Measure resistance across CANH and CANL with ignition OFF to check for proper termination (~60 Ω).
- Use oscilloscope or capable scan tool to verify CAN message traffic and look for missing heartbeat messages from the IRC or bus errors.
- Isolate wiring: disconnect nearby modules or aftermarket devices that share the bus, and re-check communication.
- If wiring and power/ground checks are good but no communication, consider reflashing or replacing the IRC per manufacturer procedure (only after confirming wiring integrity).
- Clear codes, re-establish communication, and perform test drive or re-check network to confirm repair. Document findings and any parts replaced.
- If intermittent, perform a wiggle test, road test, or use a smoke/leak test on harnesses in suspect areas to reproduce fault.
Likely causes
- Damaged/crushed wiring harness near door, dash, or seat area
- Corroded or loose IRC connector pins
- Blown fuse or poor battery connection causing module to not wake
- Missing/failed CAN termination resistor or short on CANH/CANL
- Module has internal failure
Fault status
Status
Loss of communications with IRC (Inflatable/Integrated Restraint Controller). Module not responding on vehicle network — SRS-related features may be disabled.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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Code
U1128
MITSUBISHI
U — Network/User
Meter(CAN message)
Views:
UK: 7
EN: 17
RU: 16
AI status
Completed
Completed
100%
Causes
- Open, shorted, or corroded wiring between IRC and vehicle network
- Faulty or loose connector at the IRC
- Failed IRC module
- Low battery voltage or intermittent power/ground to the IRC
- CAN bus termination or wiring fault (short to battery or ground)
- Network interference from another module or after-market device
Symptoms
- SRS/airbag warning lamp illuminated
- Scan tool cannot communicate with IRC or shows module not present
- Unable to perform airbag module data read or reprogramming
- Related safety systems disabled or reporting faults
- Occasional or permanent loss of other network messages
What to check
- Record freeze-frame, full DTC list, and active/inactive status with a scan tool
- Verify battery voltage at rest and while cranking (should be ~12.0–14.5 V)
- Inspect fuses and power/ground circuits for the IRC
- Visually inspect IRC connectors and harness for corrosion, looseness, or damage
- Attempt to communicate with the IRC using a capable scan tool
- Check for other U-codes on the network that could indicate broader bus issues
Signal parameters
- Supply voltage to IRC: approximately 11–14.5 V (vehicle battery range)
- Ground continuity: near 0 ohms to chassis ground (typically
- CAN bus idle voltages: CANH ~2.5–3.5 V, CANL ~1.5–2.5 V (dominant state will shift toward ~3.5 V / ~1.5 V)
- CAN differential (dominant) ~1.5–2.5 V when active
- Bus resistance (with network intact/terminators): ~60 Ω total (approx. 120 Ω if single-ended? — verify vehicle specific)
Diagnostic algorithm
- Follow safety procedures for SRS work: consult service manual, disconnect battery and wait the specified time before disconnecting IRC connectors.
- Connect a factory-level or qualified scan tool; record U1128 and any related codes, then attempt to communicate with the IRC.
- Verify battery voltage and check related fuses/power feeds to the IRC. Repair any blown fuses or poor battery connections.
- Inspect IRC connector and wiring for corrosion, bent pins, or physical damage. Repair or replace as needed.
- With ignition ON (battery connected), measure supply voltage and ground at the IRC connector pins. Ensure correct voltages are present.
- Check CAN network: measure CANH/CANL voltages at the IRC connector and at another module. Compare readings and look for open/short conditions.
- Measure resistance across CANH and CANL with ignition OFF to check for proper termination (~60 Ω).
- Use oscilloscope or capable scan tool to verify CAN message traffic and look for missing heartbeat messages from the IRC or bus errors.
- Isolate wiring: disconnect nearby modules or aftermarket devices that share the bus, and re-check communication.
- If wiring and power/ground checks are good but no communication, consider reflashing or replacing the IRC per manufacturer procedure (only after confirming wiring integrity).
- Clear codes, re-establish communication, and perform test drive or re-check network to confirm repair. Document findings and any parts replaced.
- If intermittent, perform a wiggle test, road test, or use a smoke/leak test on harnesses in suspect areas to reproduce fault.
Likely causes
- Damaged/crushed wiring harness near door, dash, or seat area
- Corroded or loose IRC connector pins
- Blown fuse or poor battery connection causing module to not wake
- Missing/failed CAN termination resistor or short on CANH/CANL
- Module has internal failure
Fault status
Status
Loss of communications with IRC (Inflatable/Integrated Restraint Controller). Module not responding on vehicle network — SRS-related features may be disabled.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
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Send to email
Code
U1128
Other
U — Network/User
SCP (J1850) Invalid or Missing Data for Primary Id
Views:
UK: 25
EN: 30
RU: 29
AI status
Completed
Completed
100%
Causes
- Open, shorted, or corroded wiring between IRC and vehicle network
- Faulty or loose connector at the IRC
- Failed IRC module
- Low battery voltage or intermittent power/ground to the IRC
- CAN bus termination or wiring fault (short to battery or ground)
- Network interference from another module or after-market device
Symptoms
- SRS/airbag warning lamp illuminated
- Scan tool cannot communicate with IRC or shows module not present
- Unable to perform airbag module data read or reprogramming
- Related safety systems disabled or reporting faults
- Occasional or permanent loss of other network messages
What to check
- Record freeze-frame, full DTC list, and active/inactive status with a scan tool
- Verify battery voltage at rest and while cranking (should be ~12.0–14.5 V)
- Inspect fuses and power/ground circuits for the IRC
- Visually inspect IRC connectors and harness for corrosion, looseness, or damage
- Attempt to communicate with the IRC using a capable scan tool
- Check for other U-codes on the network that could indicate broader bus issues
Signal parameters
- Supply voltage to IRC: approximately 11–14.5 V (vehicle battery range)
- Ground continuity: near 0 ohms to chassis ground (typically
- CAN bus idle voltages: CANH ~2.5–3.5 V, CANL ~1.5–2.5 V (dominant state will shift toward ~3.5 V / ~1.5 V)
- CAN differential (dominant) ~1.5–2.5 V when active
- Bus resistance (with network intact/terminators): ~60 Ω total (approx. 120 Ω if single-ended? — verify vehicle specific)
Diagnostic algorithm
- Follow safety procedures for SRS work: consult service manual, disconnect battery and wait the specified time before disconnecting IRC connectors.
- Connect a factory-level or qualified scan tool; record U1128 and any related codes, then attempt to communicate with the IRC.
- Verify battery voltage and check related fuses/power feeds to the IRC. Repair any blown fuses or poor battery connections.
- Inspect IRC connector and wiring for corrosion, bent pins, or physical damage. Repair or replace as needed.
- With ignition ON (battery connected), measure supply voltage and ground at the IRC connector pins. Ensure correct voltages are present.
- Check CAN network: measure CANH/CANL voltages at the IRC connector and at another module. Compare readings and look for open/short conditions.
- Measure resistance across CANH and CANL with ignition OFF to check for proper termination (~60 Ω).
- Use oscilloscope or capable scan tool to verify CAN message traffic and look for missing heartbeat messages from the IRC or bus errors.
- Isolate wiring: disconnect nearby modules or aftermarket devices that share the bus, and re-check communication.
- If wiring and power/ground checks are good but no communication, consider reflashing or replacing the IRC per manufacturer procedure (only after confirming wiring integrity).
- Clear codes, re-establish communication, and perform test drive or re-check network to confirm repair. Document findings and any parts replaced.
- If intermittent, perform a wiggle test, road test, or use a smoke/leak test on harnesses in suspect areas to reproduce fault.
Likely causes
- Damaged/crushed wiring harness near door, dash, or seat area
- Corroded or loose IRC connector pins
- Blown fuse or poor battery connection causing module to not wake
- Missing/failed CAN termination resistor or short on CANH/CANL
- Module has internal failure
Fault status
Status
Loss of communications with IRC (Inflatable/Integrated Restraint Controller). Module not responding on vehicle network — SRS-related features may be disabled.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email