Code 14166: [Channel %1: ] Block %2 error %3 when programming a tool length offset with TOFF / TOFFL
Issue Description & Safety Warning
The Siemens SINUMERIK 840D CNC has triggered a critical [Channel %1: ] Block %2 error %3 when programming a tool length offset with TOFF / TOFFL alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Parameters: %1 = Channel number %2 = Block number, label %3 = Error code Definitions: An error occurred while programming a tool length offs et with TOFF or TOFFL. More information about the type of error is given by the error code number: Error code 1At least one tool length offset component has been programmed twice in one block (with TOFF). 2At least one tool length offset component has be en programmed twice in one block (with TOFFL). 3Tool length offset components have been progra mmed in one block with both TOFF and TOFFL. 4An index must be declared when a tool length offs et is programmed with TOFF, the form TOFF=.... is not permissible. 5An illegal index was declared when progra mming TOFFL (permissible values 1..3). 6An illegal axis was declared as the index when programming TOFF. Only geometry axes are permitted. Reaction: Correction block is reorganized. Interface signals are set. Alarm display. Remedy: Correct errors in program block. Program Continuation: Clear alarm with NC ST ART or RESET key and continue the program.
Source: SINUMERIK 840D sl / 840Di sl / SINAMICS S120 Diagnostics Manual (DAsl, 03/2009)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Siemens SINUMERIK 840D CNC Alarms
Siemens controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code 14166 on the SINUMERIK 840D CNC identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Siemens's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 4014 Siemens SINUMERIK 840D CNC codes.
Have a better solution?
Help the industrial community by sharing your repair experience for code 14166.
Need a searchable reference for more Siemens SINUMERIK 840D CNC manuals?
We structure equipment manuals into searchable code, title, cause, solution, safety note, and source-reference data. Send a PDF and example searched codes when you need public pages, private search, or structured exports.
Space reserved for Google AdSense / Industrial Affiliate Links
Monetization target for 2026