2018 Honda Odyssey: water leaks into the cabin

Filed Oct 20, 2026 · Body, Electrical · PA

In XXX, the power tailgate on my 2018 Honda Odyssey stopped working. I took the vehicle to authorized Honda dealer Fred Beans Honda of [XXX]. The technician documented in writing on repair order #XXX (XXX): "There is water leaking onto the power tailgate control unit. Technician found the water leak going into from the back of roof on the left side. Needs a new power tailgate control unit." Water entered through the rear body seam seals and dripped onto the power tailgate control module (P/N 74970-THR-A12). The removed module showed severe blue-green corrosion -- it does not fail on its own at 31,500 miles. Safety concern: A tailgate whose control module is destroyed by water intrusion cannot be relied on to latch or stay closed; an unlatched or unexpectedly opening tailgate while driving endangers occupants and surrounding traffic. Known defect, not isolated failure: Honda issued a TSB on rear body seam-seal water intrusion on 2018-2019 Odysseys; federal class action Case No.XXX (XXX.) covers 2018-2021 Odysseys with defective polyurethane seam seals destroying the power tailgate control module; numerous owner reports in the federal safety agency database describe identical failures. What I did: The dealer quoted $1,302.88. I first asked American Honda by phone for goodwill coverage and was denied. I repaired it myself with a genuine Honda module ($215.57, Order #XXX, XXX); total out-of-pocket $416.92. On XXX I submitted a written goodwill reimbursement request online (case #XXX, continuing prior case #XXX); on XXX Honda denied it as not covered under any campaign, even though the failure is caused by the documented seam-seal defect that is the subject of the pending class action above. What I am asking the federal safety agency: record this complaint and consider investigation/recall of the 2018-2019 Odyssey seam-seal water intrusion defect. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 11, 2026 · Driver assistance, Electrical · IN

This vehicle is actively immobilized on private residential property with its central ADAS safety networks and Advanced Driver-Assist networks completely crashed and offline (DTC U3000-49) and active short-to-ground circuit failures (DTC B2035) rendering the passenger sliding doors completely inoperable, creating an immediate entrapment and safety hazard. These progressive component failures cascade directly from severe environmental moisture intrusion inside the rear tailgate enclosure. This exact water migration vector intersects directly with active federal safety campaign the federal safety agency Recall 26-V-423 (Rearview Camera Failure), which isolates moisture intrusion into the panel housing as the root factory manufacturing defect. A manufacturer franchise location documented active water leakage onto the Power Tailgate Control Unit and heavy corrosion on the wiring connector under a previous Repair Order but performed zero interim moisture sealing, corrosion cleanup, or terminal mitigation, allowing progressive water migration to completely destroy the wiring system harness. Furthermore, American Honda Corporate Case Management explicitly stated on a recorded verbal line that the manufacturer is denying all repair assistance to remedy these cascading safety campaign electrical defects under an active corporate case. The manufacturer is in open default of its statutory federal obligation to remedy a safety recall defect free of charge to the consumer.

Filed Sep 7, 2026 · OH

Tail gate problems Looks like there are a lot of tailgate problems with the Honda Odyssey, including water leaks that can affect the control module. I replaced the control module, but it looks like there’s a lot of information and research about this issue online.

Filed Jul 10, 2026 · Electrical, Lights · 144,411 miles · IL

The contact owns a 2018 Honda Odyssey. The contact stated that while a customer on Turo was driving the vehicle, the instrument panel warning lights flashed and the climate control system failed to function. The vehicle was restarted multiple times, but the instrument panel warning lights remained illuminated. The contact stated that while being driven, the vehicle was pulled over by law enforcement because the taillights failed completely. The vehicle was taken to the dealer, where it was diagnosed that the gauge control module had failed due to corrosion from water damage. Upon further inspection during the replacement, the dealer discovered additional failures within the body control module and the taillight wiring harness. Technicians determined that the electrical failures were caused by water leaking from the rear windshield into the tailgate area. The vehicle was repaired; however, the water leak source was not addressed or sealed. The manufacturer was notified of the failure. The failure mileage was 144,411.

Filed May 29, 2026 · Electrical · FL

COMPONENT: Power Liftgate Control Module (PTG module). Vehicle is available for inspection upon request. WHAT HAPPENED: On approximately April 7, 2026, while driving in rain, a "Power Tailgate Problem" warning appeared on the instrument cluster. Following that event, all powered liftgate operation became permanently inoperable — interior button, exterior button, and key fob all failed. CAUSE: An authorized Honda dealer confirmed in writing (service invoice, May 1, 2026): "Power Liftgate Control Unit has corrosion from water leak." The water intrusion originates from defective factory polyurethane seam sealer on the rear drip rail — a known manufacturing defect on 2018-2019 Odysseys documented in Honda TSB MC-10152401. SAFETY RISK: The same water intrusion that destroys the PTG module is documented to cause the liftgate to open unexpectedly while driving, posing a direct hazard to occupants and other motorists. the federal safety agency is already investigating this issue across 2018-2022 Odysseys. WARNING SYMPTOMS: "Power Tailgate Problem" warning on instrument panel cluster appeared during rain exposure prior to full failure. MANUFACTURER RESPONSE: American Honda Motor Co. declined to cover the repair under goodwill despite the dealer-confirmed defect, an active TSB, and an ongoing class action lawsuit (2018-2021 Odysseys) for this exact issue. Honda has not issued a recall. Estimated repair cost: $691 (module) plus body seam repair.

Filed May 18, 2026 · NY

Rear hatch latch failure. Seal failure resulting in water leak, causing electronic failure. Risk off items falling out of vehicle causing road hazards. Independent repair shop unable to diagnosis/repair. Dealer able to make repairs as they were familiar with the problem, had made many similar repairs. No warning lamps prior to issue, light/alarm when issued occurred. Honda Corporate customer service declined “goodwill” repair.

Filed Feb 27, 2026 · Body · NY

​I am filing a formal safety complaint regarding a dangerous manufacturing defect in my 2018 Honda Odyssey EX . A structural failure of the factory roof seam sealer (ditch molding) is allowing rainwater to pour directly into the vehicle's cabin, severely compromising critical electrical modules and creating major safety hazards. ​This water intrusion has caused two distinct and dangerous electrical failures: ​1. Entrapment Hazard (Power Sliding Doors): Previously, water leaked into the rear fuse box area, causing the power sliding doors to completely fail and become completely unopenable. Transporting a [XXX] and a [XXX] in the rear seats, the sudden inability to open the sliding doors creates a terrifying entrapment hazard. In the event of an accident, fire, or emergency, I would be unable to evacuate my young children from the rear cabin quickly, posing an immediate threat to their lives. ​2. Cargo and Security Hazard (Power Tailgate Control Module): Currently, the water leak has short-circuited the Power Tailgate Control Module. The system operates erratically: the tailgate automatically pops open as soon as the engine is turned off, and it refuses to open manually. Beyond the security risk, this electrical short could cause the tailgate to unlatch unexpectedly while the vehicle is in motion or stopped in traffic, potentially dropping cargo onto the roadway and creating a crash hazard for other drivers, or allowing carbon monoxide exhaust to enter the passenger cabin. ​This is a well-documented and widespread structural defect affecting many 2018-generation Honda Odysseys. Water destroying critical safety modules (doors and tailgates) is a severe design flaw that goes far beyond normal wear and tear. ​I strongly urge the federal safety agency to open a formal investigation into the roof seam sealer failures on the 2018 Honda Odyssey. A safety recall is necessary to force Honda to repair the structural leaks and replace the compromi INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 15, 2026 · Electrical · CA

Defective body seam on roof panel over drivers side rear wheel - resulting water leak on control panel for power liftgate caused the rear tailgate to continually open and close while driving. The vehicle was parked and the fuses controlling the tailgate were removed to enable the closure of the hatch and allow vehicle operation. Prior to this, the vehicle battery died while parked due to the continuous tailgate operation and required a battery jump. The vehicle was taken to D&J Auto (an independent service center) where a previous liftgate control panel was replaced for failure to open the tailgate. A search of the internet on 2018 Honda Odyessey liftgate problems revealed multiple instances of water leaks on the liftgate control panels due to body seam issues which caused liftgate failures. This information was relayed to the auto repair shop where the leak was discovered. The vehicle was taken to a body repair shop across the street where the seam was fixed, returned to the auto repair shop where a third tailgate control panel installed.

Filed Feb 10, 2026 · VA

Water leaked through manufacting seams on rear drivers side of roof causing tailgate module to malfunction and creating a safety hazard. The rear tailgate would not stay latched or function at all. Took vehicle to honda of Bristol and they confirmed the problem.

Filed Sep 27, 2025 · Electrical · FL

Like many other people on the [XXX] forums, our Honda Odyssey has a water leak that dripped onto the Tailgate Control Module, causing it to corrode and stop working. Now, our tailgate door will not open or close electrically, nor even manually using the handle outside. We have to crawl through the vehicle into the trunk, open a trim piece with a screwdriver, and stick our finger into the mechanical parts to disengage the latch to allow the door to open. Safety issues: 1) It's hard to know whether the door is fully closed and latched, so it could pop open while driving. 2) In the event of a car crash or other emergency, we may need to rely on that tailgate door being operational, so it being jammed by a widespread and known problem seems like a predictable life threatening issue. Links to some of the forum threads where other people report the exact same issue: [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Aug 22, 2025 · Driver assistance, Electrical · FL

In our 2018 Honda Odyssey EX-L, a few weeks ago 5 different warning lights started coming on when the vehicle was started and continued while the car was driven. Lane Assist, collision warning, auto high beams, braking system and adaptive cruise control. Just yesterday the rear hatch started to malfunction; currently the rear hatch can be opened and closed manually but the power lift does not function and now is the 6th warning on the driving display. The car was taken to a Honda Dealership for diagnosis, and after paying $99 for the diagnosis of the issues, several other diagnosis fees would be required to get to the root of the issue which the Tech states is most likely a control module malfunction due to a water leak. The fix would then be finding and fixing the leak, then replacing the module and wrapping the module in plastic to prevent future issues. Then more diagnosis fees to find and correct the other issues which could include replacing the multipurpose camera. -If a selling point of the driver assist, collision warning and automatic braking are safety improvements, by default if the system is faulty then ours and others safety is at an increased risk. -the vehicle has been inspected by a dealer -before a few weeks ago no warning lamps, messages or other symptoms were present. All of the symptoms have been rather sudden. We have been getting rain almost daily for the past few weeks.

Filed Jun 24, 2025 · Body, Electrical · FL · 2 injuries

Crack in body seam above driver and passenger side of the tailgate AND underneath the roof rail cover caused water leakage. This resulted in a short of the power tailgate control module which draws down my battery and causes unexpected trunk closing during normal use. Family members have been hit in the head by the trunk due to the unexpected automatic emergency closing.