P1750

P1750 is a Mitsubishi-specific code meaning the TCM detected a fault in the Transmission Control Solenoid circuit — typically the line-pressure solenoid (PCS) or one of the shift solenoids (SS-A/SS-B) on the F4A4 / F5A5 / W5A5 family of 4- and 5-speed automatics, or a stepper-motor fault on the JATCO CVT. The TCM monitors solenoid current draw against a reference window; out-of-range current sets P1750 along with a sub-code identifying which solenoid. Cheapest-first ladder: (1) Check ATF level and condition — Mitsubishi's automatics are intolerant of overdue fluid, and burnt fluid with a varnish smell will gum solenoid spools and trigger P1750 long before mechanical failure ($0, 5 min, run engine warm with selector in N per Mitsubishi FSM). (2) Scan live data and command each solenoid individually with bidirectional control — a healthy Mitsubishi PCS shows 0.3-1.0A duty-cycled at idle (line pressure modulation), and shift solenoids show clean on/off transitions at 0V or 12V; a solenoid stuck at 0A or pegged at the upper current limit identifies the failed unit. (3) Ohm each solenoid at the trans connector — Mitsubishi spec is 3-7 ohms for shift solenoids and 4-8 ohms for the PCS at room temp; open circuit (infinite ohms) or short to ground (under 1 ohm) means failed coil. (4) Pan drop and inspect for clutch material before any solenoid replacement — fine bronze flake or black clutch dust means the solenoid is a symptom of a wearing pack, and replacing only the solenoid leaves the root cause in place. Expensive-misdiagnosis caveat: don't replace the entire valve body for P1750 before checking the internal connector at the trans bulkhead — Mitsubishi's bulkhead connector is a known leak point, and ATF migration along the harness wicks into the body-side connector and corrodes the TCM pins, mimicking solenoid failure; the fix is a $40 connector pigtail and reseal, not an $1,800 valve body.

Vehicle-specific patterns: 2002-2007 Mitsubishi Lancer 2.0L (4G94) with the F4A4 4-speed throws P1750 from PCS contamination at 100-130k miles — the line-pressure solenoid is the first to fail because it duty-cycles continuously. 2004-2011 Mitsubishi Galant 2.4/3.8L with the F4A5/W5A5 family commonly throws P1750 from shift-solenoid B failure that causes a 2-3 shift flare before the code sets. 2003-2008 Mitsubishi Endeavor 3.8L and 2006-2012 Eclipse 3.8L share the W5A5 5-speed and the same shift-solenoid failure mode. 2007-2013 Mitsubishi Outlander 3.0L (6B31) with the F4A5 4-speed (pre-CVT models) sees P1750 from the same PCS contamination; the CVT variants throw a different P175x sub-code for stepper-motor faults. 2001-2006 Mitsubishi Montero Sport 3.5/3.8L (V4AW3-equipped) throws P1750 from harness chafe where the trans harness crosses the bellhousing flange. Estimated repair: $80 to $2,200.