U0140: How to Diagnose & Fix — Lost Communication with BCM

The S-TYPE is notorious for electrical gremlins caused by moisture ingress into control modules and poor CAN bus connections. Phantom warning lights, inoperative features, and intermittent faults across multiple systems are common and difficult to diagnose without dealer-level equipment.

The Dodge Magnum suffers from widespread electrical problems centered around the TIPM (Totally Integrated Power Module) and the steering column control module (clockspring). Symptoms include dash lights flickering or going completely dark while driving, headlights cutting out at night, loss of turn signals, wipers, horn, and cruise control all at once. The steering column module failure is particularly dangerous as it can disable multiple safety systems simultaneously. The TIPM relay failures can cause no-start conditions, fuel pump cutouts, and random electrical gremlins throughout the vehicle.

Ford Transit BCMs, particularly on 2015–2019 models, have been reported to fail or develop software faults causing a wide array of seemingly unrelated electrical issues including random door lock cycling, instrument cluster malfunctions, and accessory power loss. Water intrusion from sunroof drains or cowl leaks can accelerate BCM failure by corroding the module's internal connectors. Ford Special Service Message 47094 notes that 2015-2017 Transits may fail BCM installation programming when a new body control module is installed.

The second-row captain's chairs equipped with power adjustment and memory functions on Grand Wagoneer L and standard models have been reported to fail to return to memorized positions or become entirely non-operational. The seat position memory module loses stored settings after a battery event, and the seat track actuator motors can bind in the rearmost position, blocking third-row access. Owner complaints on forums and NHTSA describe seats that move to a position and stop mid-travel, or refuse to respond to the Easy Entry function.

The Dodge Challenger has two distinct, well-documented power-steering complaints on the pre-2015 LC/LX-platform cars, and both are flagged by RepairPal as common problems (MotorBiscuit lists "a loud power steering system" among the four most-reported Challenger issues). FIRST, a HYDRAULIC NOISE: owners hear a honk, hiss, groan, or whine from the steering during low-speed parking-lot maneuvers, worst when turning the wheel toward full lock. RepairPal documents this as a recognized concern on 2008-2012 Challengers; Chrysler addressed it with TSB 19-005-10 ("Steering Gear Honk, Hiss or Groan During Low Speed Parking Lot Maneuvers," superseding 19-003-09), which traces the noise to the power-steering return hose and, in some cases, the steering gear (rack). Fluid aeration, a low or contaminated fluid level, and worn pump vanes/bearings produce the same groan/whine. SECOND, an ASSIST-LOSS failure on EHPS cars: 2011-2014 Challengers with the 3.6L Pentastar or 5.7L HEMI use an electro-hydraulic power-steering (EHPS) pump that depends on the charging system. Under NHTSA recall 17V-435 (Chrysler recall T36, ~442,214 vehicles across Challenger/Charger/300/Durango/Grand Cherokee), the alternator can suffer diode thermal fatigue specifically because of the cyclical electrical loads the EHPS pump imposes; when the diodes fail, system voltage drops, the EHPS pump shuts down, the steering goes heavy, and the vehicle can stall without warning (failed diodes can also short and cause heat/smoke/fire). Note the engine/fluid split: 3.6L/5.7L EHPS cars require Mopar Electric Power Steering Fluid, while the conventional hydraulic SRT8/392 (6.1L/6.4L) and base V6 systems use ATF+4 — using the wrong fluid causes noise, seal damage, and pump failure. This entry is distinct from the electric power steering used on the 2015+ refreshed Challenger, which is a different rack design and root cause.