U02A9 on Dodge: How to Diagnose & Fix
Lost Communication With Charge Air Cooler Coolant Pump "A"
1 Dodge model · 1 documented issue · $140-$1,200 repair
U02A9 on Dodge by model: symptoms, diagnosis and fix
A widely reported electrical complaint across nearly all Challenger model years is excessive parasitic battery drain that leaves the car dead overnight or after sitting a few days. A healthy modern vehicle should settle to roughly 25-50 mA of key-off draw once all modules go to sleep; owners reporting this problem measure anywhere from several hundred milliamps to over 2-4 amps, which is enough to flatten a battery in a day or two. There are several distinct, real-world root causes documented across owner forums (ChallengerTalk, ChallengerForumz, Hellcat.org), NHTSA/CarComplaints filings, and repair sites: 1) Smart-glass / one-touch power window self-cycling — the single most-reported cause in NHTSA and CarComplaints/CarProblemZoo data (18+ "battery dead" reports concentrated on 2010-2014, plus 2018). A faulty window switch or window module causes the driver- or passenger-side glass to drop and raise itself a fraction of an inch repeatedly with the key off, running the motor until the battery is dead. Chrysler issued a recall on 2011 cars for a related concern, but owners of 2012+ report the same symptom with no recall. 2) TIPM (Totally Integrated Power Module) faults — the under-hood power/fuse-relay computer controls dozens of circuits and can keep a circuit "awake" or stick a relay closed, producing a steady ~1-2 A draw. TIPM failure is a known weak point on Chrysler/Dodge platforms and a common diagnosis on early (2008-2014) cars. 3) Infotainment / Uconnect radio (RER, 730N, and later Uconnect head units) not entering sleep mode — a hung or buggy radio keeps the accessory bus awake. Owners report dealers pulling the radio fuse to confirm, then resolving it with a head-unit software re-flash (e.g., updating to 18.45.01) or radio replacement; multiple owners also report repeated radio/touchscreen failures on 2015-2017 cars. 4) Stuck switches and accessories — faulty door-jamb/courtesy switches that keep a dome light on, a trunk/glovebox/vanity light staying on, door-lock actuator faults, or aftermarket add-ons (alarms, amps, dash cams) wired to a constant-hot circuit. 5) Alternator diode failure — a shorted rectifier diode lets current bleed backward through the alternator with the engine off; some owners also have a charging fault where the PCM voltage regulation is at fault, so a new alternator alone does not fix it. 6) Hellcat / supercharged charge-air-cooler (intercooler) auxiliary coolant pump not shutting off — on 2015+ supercharged cars the aux pump can fail to power down (often after coolant intrudes into the connector or a loose intake-box ground), running the pump and killing the battery in as little as 3 days; this typically also sets charge-air-cooler pump DTCs (P023B, U02A9). SRT models from 2018+ include a "Storage Mode" that reduces key-off draw and should be enabled when parking.
Common Symptoms
- Battery dead the next morning or after the car sits a few days
- Car needs a jump-start frequently despite a relatively new battery
- Power window drops and raises itself a fraction of an inch with the key off / ignition off
- Audible relay clicking or a motor/pump running after the car is shut off and locked
- Key-off parasitic draw measures well above the normal ~25-50 mA (often hundreds of mA to 2-4 A)
- New battery still goes dead and alternator tests fine
- Infotainment/Uconnect radio or touchscreen freezing, restarting, or failing to power down
- Hellcat intercooler/charge-air pump stays warm and running after shutdown
- Battery/charging warning light or flickering dash lights
- Dome, trunk, or courtesy light staying on with doors closed
How to Fix
Confirm the charging system first: load-test the battery and verify alternator output with a multimeter, including an AC-ripple check to catch a failing diode (a new battery that keeps dying with a "good" charging test points to parasitic draw, not the battery). Then perform a key-off parasitic-draw test: let the car fully sleep (30-60 minutes, doors closed), put a meter in series with the negative battery cable, and confirm the draw. Anything sustained above ~50 mA is suspect; over ~250 mA will flatten the battery overnight. Isolate the offending circuit by pulling fuses/relays one at a time (both the under-hood and trunk-area fuse boxes) and watching for the draw to drop. Common findings and fixes: - Power-window self-cycling: replace the faulty window switch or window/door module and reset window auto-up programming; have the dealer check for any applicable recall/extended-warranty coverage. - Radio/Uconnect not sleeping: confirm by pulling the radio fuse; fix with a head-unit software re-flash/update or replace the head unit if it won't sleep. - TIPM keeping a circuit awake or a stuck relay: swap/replace the suspect relay or, if confirmed, the TIPM. - Stuck door/courtesy/trunk switch or stuck dome light: replace the faulty switch. - Alternator diode: replace the alternator (and verify PCM charging control if the fault persists). - Hellcat charge-air-cooler aux pump not shutting off (P023B / U02A9): inspect/clean the intake-box ground and the pump connector for coolant intrusion; replace the auxiliary coolant pump if it won't power down. - Aftermarket accessories: move any constant-draw add-ons to a switched/ignition circuit. When storing the car, enable SRT "Storage Mode" (2018+ SRT, via steering-wheel/center-display menu) or use a battery maintainer/trickle charger to prevent recurrence.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Innova 3320 auto-ranging digital multimeter
Its DC10A input is unfused and the manual limits high-current readings; incorrect series connection can damage the meter or vehicle, so use the exact manual procedure and a current clamp/professional diagnosis when the draw may exceed th…
- NOCO GENIUS5 five-amp charger, maintainer and desulfator
Long-term-storage support after the battery and charging system are known good, or while an infrequently driven vehicle is stored Fitment: Universal 6V/12V lead-acid including AGM and lithium support; it does not locate or repair a paras…
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Sources for this issue (1)
U02A9 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U02A9 mean on a Dodge?
U02A9 stands for "Lost Communication With Charge Air Cooler Coolant Pump "A"." A generic network/communication code for vehicles using a liquid-to-air charge air cooler with its own electrically driven, module-controlled coolant pump. It is documented by GM (for example on the 3.0L Duramax diesel, TSB 23-NA-102) and is also commonly reported on supercharged Stellantis SRT models (Charger/Challenger Hellcat). The code sets when the controlling module stops receiving valid messages from the charge air cooler coolant pump — often over the LIN bus, so it may appear with U1345 (LIN bus failure). Because the pump circulates coolant through the intercooler, a genuine loss of pump function means rising intake air temperatures and reduced power under load. It is frequently reported alongside P023B (charge air cooler coolant pump control circuit) and is usually an electrical/connector path problem rather than a dead pump. On Dodge it is documented across 1 model: Challenger.
What are the most common causes of U02A9?
The most common causes of U02A9 are: Unsealed, wet, or corroded connector at the charge air cooler coolant pump (a documented GM failure mode — water intrusion into the pump connector), Damaged or chafed wiring, including harness contacting the radiator, Blown fuse or failed relay in the pump module's power feed, Poor or corroded ground causing intermittent dropout under heat and vibration, LIN/serial data bus fault between the pump module and the controlling module, Failed charge air cooler coolant pump module. The specific cause varies by vehicle.
How much does it cost to fix U02A9 on a Dodge?
Published repair estimates on Dodge range from $140 to $1,200 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for U02A9 on a different make?
View U02A9 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.