U0147 — Lost Communication With Serial Data Gateway Module B

Causes

• Power or ground fault to Gateway Module B
• Damaged or disconnected connector(s) at the gateway or along the data bus
• Faulty Gateway Module B (internal failure)
• Open, short, or high resistance in CAN/LIN/serial data wiring
• Missing or incorrect network termination resistor(s)
• Intermittent wiring fault (corrosion, chafing, broken wire)

Symptoms

• One or more control modules not present on scan tool or showing ‘no communication’
• Multiple unrelated warning lights or modules reporting errors
• Loss of features that require networked modules (e.g., instrument cluster info, infotainment, remote functions)
• Intermittent or permanent inoperative systems that route through the gateway
• Stored U0147 with or without other U-codes

What to check

• Read current and pending codes from ALL modules with a capable scan tool; note other network-related U-codes
• Verify vehicle battery voltage (12V nominal) and charge level during testing
• Inspect fuses and relays supplying Gateway Module B
• Visually inspect connectors and wiring to the gateway and along the main data bus for corrosion, damage, or disconnection
• Use a scan tool to confirm whether Gateway Module B is present and responding on the network
• Check for noise, high error counters, or bus-off states on CAN/LIN networks by viewing network data or error counters with a diagnostic tool

Signal parameters

• Battery voltage: 12.0–14.5 V during testing
• CAN bus idle: CANH ≈ 2.5 V, CANL ≈ 2.5 V (small difference ~0 V)
• CAN dominant state: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ~2 V)
• Termination resistance: ~120 Ω across CANH–CANL measured at vehicle harness ends (approx. 60 Ω when measured from one end to center of split)
• LIN bus idle typically near battery or ground reference depending on vehicle (check manufacturer spec)
• Message rate: expected periodic gateway heartbeat frequency and presence of module-specific messages (use scan tool)

Similar codes

Causes

• Power or ground fault to Gateway Module B
• Damaged or disconnected connector(s) at the gateway or along the data bus
• Faulty Gateway Module B (internal failure)
• Open, short, or high resistance in CAN/LIN/serial data wiring
• Missing or incorrect network termination resistor(s)
• Intermittent wiring fault (corrosion, chafing, broken wire)

Symptoms

• One or more control modules not present on scan tool or showing ‘no communication’
• Multiple unrelated warning lights or modules reporting errors
• Loss of features that require networked modules (e.g., instrument cluster info, infotainment, remote functions)
• Intermittent or permanent inoperative systems that route through the gateway
• Stored U0147 with or without other U-codes

What to check

• Read current and pending codes from ALL modules with a capable scan tool; note other network-related U-codes
• Verify vehicle battery voltage (12V nominal) and charge level during testing
• Inspect fuses and relays supplying Gateway Module B
• Visually inspect connectors and wiring to the gateway and along the main data bus for corrosion, damage, or disconnection
• Use a scan tool to confirm whether Gateway Module B is present and responding on the network
• Check for noise, high error counters, or bus-off states on CAN/LIN networks by viewing network data or error counters with a diagnostic tool

Signal parameters

• Battery voltage: 12.0–14.5 V during testing
• CAN bus idle: CANH ≈ 2.5 V, CANL ≈ 2.5 V (small difference ~0 V)
• CAN dominant state: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ~2 V)
• Termination resistance: ~120 Ω across CANH–CANL measured at vehicle harness ends (approx. 60 Ω when measured from one end to center of split)
• LIN bus idle typically near battery or ground reference depending on vehicle (check manufacturer spec)
• Message rate: expected periodic gateway heartbeat frequency and presence of module-specific messages (use scan tool)

Similar codes

Causes

• Power or ground fault to Gateway Module B
• Damaged or disconnected connector(s) at the gateway or along the data bus
• Faulty Gateway Module B (internal failure)
• Open, short, or high resistance in CAN/LIN/serial data wiring
• Missing or incorrect network termination resistor(s)
• Intermittent wiring fault (corrosion, chafing, broken wire)

Symptoms

• One or more control modules not present on scan tool or showing ‘no communication’
• Multiple unrelated warning lights or modules reporting errors
• Loss of features that require networked modules (e.g., instrument cluster info, infotainment, remote functions)
• Intermittent or permanent inoperative systems that route through the gateway
• Stored U0147 with or without other U-codes

What to check

• Read current and pending codes from ALL modules with a capable scan tool; note other network-related U-codes
• Verify vehicle battery voltage (12V nominal) and charge level during testing
• Inspect fuses and relays supplying Gateway Module B
• Visually inspect connectors and wiring to the gateway and along the main data bus for corrosion, damage, or disconnection
• Use a scan tool to confirm whether Gateway Module B is present and responding on the network
• Check for noise, high error counters, or bus-off states on CAN/LIN networks by viewing network data or error counters with a diagnostic tool

Signal parameters

• Battery voltage: 12.0–14.5 V during testing
• CAN bus idle: CANH ≈ 2.5 V, CANL ≈ 2.5 V (small difference ~0 V)
• CAN dominant state: CANH ≈ 3.5 V, CANL ≈ 1.5 V (differential ~2 V)
• Termination resistance: ~120 Ω across CANH–CANL measured at vehicle harness ends (approx. 60 Ω when measured from one end to center of split)
• LIN bus idle typically near battery or ground reference depending on vehicle (check manufacturer spec)
• Message rate: expected periodic gateway heartbeat frequency and presence of module-specific messages (use scan tool)

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