P1700
Transmission Control Module Requested MIL Illumination
What it means
P1700. Transmission Control Module Requested MIL Illumination. This Chevy-enhanced code applies to Silverado, Sierra, Tahoe, Yukon, Suburban.
Findings, check these first
- Stored TCM fault requesting MIL illumination from the ECM
- Open or short in the TCM MIL request signal circuit
- Outdated TCM calibration
- Low transmission fluid causing companion TCM codes
- Faulty transmission control module
Standard procedure
- Scan the TCM for stored transmission codes with a Tech2 or GDS2 scan tool
- Diagnose all TCM codes first since P1700 is a request-only code
- Check transmission fluid level and condition
- Verify TCM calibration is current and update if a newer calibration exists
- Repair the underlying transmission fault, then clear both modules and road test
Look up another code
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Sources and review
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Last updated 2026-09-13.
Report a correction for P1700. Include your vehicle, the issue and a source if you have one.