P1825
WysokiInternal transmission mode switch – incorrect signal range. The transmission control module (TCM/PCM) reads an invalid combination of signals from the gear selector lever position switch.
OBD-II (EN): Transmission Range Sensor Circuit Range/Performance
Code P1825 means the transmission control module detected an invalid combination of signals from the Internal Mode Switch. This can cause incorrect automatic transmission operation and even a lock in limp mode. The cause can be a damaged switch, wiring problem, or incorrect adjustment – it is worth having a specialist perform diagnostics.
Symptoms
- Illumination of the Check Engine light (MIL) - Transmission may lock in limp mode, limiting available gears - Incorrect or no transmission range indication (P/R/N/D) on the dashboard - Hard or delayed gear shifts, jerking while driving - Possible lack of response to range change (e.g., reverse not recognized) - Engine may not start (no Park/Neutral position signal)
Possible causes
- Damaged or worn Internal Mode Switch (MLPS) - Open circuit, short circuit, or corrosion in the IMS switch wiring harness - Incorrect adjustment/position of the IMS switch relative to the gear selector shaft - Damaged IMS switch electrical connector (oxidation, loose pins) - TCM/PCM module fault (rare – diagnose after excluding other causes)
Affected systems
Does code P1825 require professional diagnostics?
The code alone is not enough. To find the cause, you need to read live data, check freeze frame conditions, and compare with vehicle behavior. Book a diagnostic session.