U2105 on Saab
CAN Bus — No Communication With ECM/ECU (Manufacturer-Specific)
U2105 on Saab vehicles indicates can bus — no communication with ecm/ecu (manufacturer-specific). Au7o has documented this code across 1 Saab model — most commonly on 9-3. U2105 is a manufacturer-specific CAN bus code that generally means a module reported no communication with the engine control module (ECM/ECU) over the network. When the ECM cannot be reached, engine-related coordination breaks down, which can cause drivability problems, no-start conditions, or multiple warning lights. Because it can affect the engine controller, it should be addressed promptly.
Common Causes of U2105
- •ECM not powered (blown fuse, failed relay)
- •Damaged or open CAN bus wiring to the ECM
- •Faulty engine control module
- •Loose or corroded ECM connector
- •Poor ground or high-resistance ground
- •Low or unstable battery voltage
- •Module configuration / programming error
U2105 on Saab by Model
Saab 9-3(1 issue)
- 9-3 Sunroof Drain Clog → Soaked Carpet → DICE/TWICE Module Failure2003-2011
Second-gen 9-3 (2003-2011) sunroof drains clog with debris (pollen, leaves). Water then overflows into the headliner, runs down the A-pillars, soaks the carpet, and pools in the front footwell — directly under the DICE (Driver Information Central Electronics) and TWICE modules. Wet modules can short and cause a cascade of weird electrical faults (no-start, dead instrument cluster, ABS faults, etc.).
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View U2105 across all makes →Frequently Asked Questions
What does U2105 mean on Saab?▼
U2105 stands for "CAN Bus — No Communication With ECM/ECU (Manufacturer-Specific)." U2105 is a manufacturer-specific CAN bus code that generally means a module reported no communication with the engine control module (ECM/ECU) over the network. When the ECM cannot be reached, engine-related coordination breaks down, which can cause drivability problems, no-start conditions, or multiple warning lights. Because it can affect the engine controller, it should be addressed promptly. On Saab specifically, this code is documented across 1 model.
What causes U2105 on Saab vehicles?▼
Common causes on Saab: ECM not powered (blown fuse, failed relay), Damaged or open CAN bus wiring to the ECM, Faulty engine control module, Loose or corroded ECM connector, Poor ground or high-resistance ground. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U2105 on a Saab?▼
Repair costs vary widely depending on the root cause and specific Saab model.
Which Saab models have U2105 documented?▼
Au7o has documented U2105 on 1 Saab model: 9-3.