U1177
Invalid Or Missing Data For Primary Id
U1177 is an OBD-II diagnostic trouble code meaning: Invalid Or Missing Data For Primary Id. Common causes: malfunction of the main identification module, open or short circuit in the can bus. Estimated repair cost: $17–278.
Symptoms
- Illumination of the fault warning lamp (Check Engine)
- Incorrect operation of systems that depend on primary module data
- Possible problems starting the engine
- Reduced engine performance
- Loss of communication with other vehicle systems
Causes
- Malfunction of the main identification module
- Open or short circuit in the CAN bus
- Problems with module power or grounding
- Corroded or damaged electrical connectors
- Software error in one of the ECUs
How to Fix
- CAN bus diagnostics using an oscilloscope
- Checking power and grounding of all network modules
- Visual inspection of connectors and wiring for damage
- Scan all modules for additional fault codes
- Flashing or replacing a faulty module
Related codes
FAQ
What does the U1177 code mean?
U1177 is an OBD-II diagnostic trouble code that indicates: Invalid Or Missing Data For Primary Id
What causes a U1177 error code?
The most common causes of U1177 include: Malfunction of the main identification module; Open or short circuit in the CAN bus; Problems with module power or grounding; Corroded or damaged electrical connectors.
How do I fix a U1177 diagnostic trouble code?
To fix U1177: CAN bus diagnostics using an oscilloscope. Checking power and grounding of all network modules. Visual inspection of connectors and wiring for damage. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U1177?
Limited driving only, diagnose soon
How much does it cost to fix U1177?
The estimated repair cost for U1177 is $17–278. Actual cost depends on your vehicle, location, and labor rates.
See also: Russian version · NationStat