P1825
Internal Mode Switch Invalid Range
What it means
P1825. Internal Mode Switch Invalid Range. This Chevy-enhanced code applies to Silverado, Sierra, Tahoe, Yukon, Impala, Malibu.
Findings, check these first
- Faulty internal mode switch reporting an invalid A/B/C/P combination
- Misadjusted shift cable leaving the manual valve between detents
- IMS and ECM Park/Neutral signal disagreeing due to circuit fault
- Metallic debris on control solenoid valve assembly electrical pins
- Worn manual shift shaft detent assembly
Standard procedure
- Compare IMS logic states to the IMS logic table with a Tech2 scan tool
- Verify shift cable adjustment and ECM Park/Neutral parameter in all ranges
- Compare TFP switch states against IMS readings for mismatch
- Inspect the control solenoid valve assembly pins for metallic debris
- Replace the IMS assembly if the invalid range persists after circuit checks
Look up another code
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Sources and review
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Last updated 2026-09-13.
Report a correction for P1825. Include your vehicle, the issue and a source if you have one.