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Home/DTC Codes/Pontiac/Sunfire/1995-2005 2.2L I4/U0009
U0009

High Speed CAN Communication Bus Shorted Together

1995-2005 Pontiac Sunfire 2.2L I4

Critical SeverityNetworkGeneric (SAE)

Description

CAN H and CAN L wires are shorted to each other, preventing differential signaling on the bus.

Symptoms

  • Complete CAN bus failure
  • No communication with any module on bus
  • Vehicle may not start

Common Causes

  • CAN H and CAN L wires shorted together
  • Connector pin damage
  • Crushed wiring harness
  • Rodent damage to wiring

Diagnostic Steps

  1. Measure resistance between CAN H and CAN L (should be ~60 ohms with termination)
  2. Inspect wiring for physical damage
  3. Check connectors for bent pins
  4. Disconnect modules and measure resistance at each segment

Repair Notes

Locate the short between CAN H and CAN L. Common in door jambs and under-dash wiring.

Related Codes

U0001High Speed CAN Communication BusU0003High Speed CAN Communication Bus (+) OpenU0006High Speed CAN Communication Bus (-) Open

Other Network Codes

U0009 on Other Vehicles

Pontiac Aztek

2001-2005 3.4L V6

Pontiac Bonneville

1990-1999 3.8L V6

Pontiac Bonneville

2000-2005 3.8L V6

Pontiac Bonneville GXP

2000-2005 4.6L V8

Pontiac Bonneville GXP

2000-2005 4.6L V8 Northstar

Pontiac Bonneville SSEi

1992-1999 3.8L Supercharged V6

Pontiac Bonneville SSEi

1992-1999 3.8L V6 Supercharged

Pontiac Firebird

1993-1997 3.4L V6

Common Questions

What does code U0009 mean on a 1995-2005 Pontiac Sunfire?

U0009 stands for "High Speed CAN Communication Bus Shorted Together". CAN H and CAN L wires are shorted to each other, preventing differential signaling on the bus.

What are the symptoms of U0009 on a Pontiac Sunfire?

Common symptoms of U0009 include: Complete CAN bus failure, No communication with any module on bus, Vehicle may not start.

What causes U0009 on a 1995-2005 Pontiac Sunfire?

Common causes of U0009 include: CAN H and CAN L wires shorted together, Connector pin damage, Crushed wiring harness, Rodent damage to wiring.

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