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2003 Dodge Durango 5.9L - PO455, PO138, PO442 Codes Fixed at 93K Miles | EVAP System Repair Guide

Model: 2003 Durango Fault Code: P0138 Posted: 2010-04-29 14:48

Hi everyone, This forum has been incredibly helpful to me—special thanks to Jeff Compton for his detailed and patient guidance. I’m sharing my experience here so that new garage mechanics or DIYers can follow a clear, step-by-step process to fix common OBD2 codes without needing expensive repairs. When the check engine light comes on, turn the key ON (without starting the engine) three times. After the third attempt, your odometer should begin flashing diagnostic trouble codes (DTCs). Write them down—they’re essential for diagnosing issues. I was experiencing PO455 and PO442 codes, which indicate large and small evaporative (EVAP) system leaks respectively. Upon inspection, I found cracks in all the EVAP hoses—especially at their connection points where they slip into fittings. These are common failure points over time. My 2003 Dodge Durango’s EVAP canister is located on the driver's side, ahead of the rear wheel and just in front of the fuel tank. To access it, I initially thought I’d need to drop the fuel tank—but Jeff’s guidance suggests there may be a less invasive method (I’ll update if I find one). There are two hoses running from the canister to the front of the truck, plus one thick U-shaped hose. I replaced all three with OEM 5/16-inch hoses purchased directly from the Dodge dealership. I also replaced the gas cap—even though the rubber gasket appeared intact and there were no visible cracks—because EVAP leaks often originate at this point. To access the under-hood components, I removed the driver-side fuse box and disconnected the negative battery terminal for easier maneuvering. The hoses run beneath the fuse box and around the back of the battery. Under the hood, locate a black hose feeding into a 'T' fitting with a green cap on the driver’s side. This is where I replaced one hose. The hose exiting the 'T' runs under the fuse box and wraps around the battery—this leads to what appears to be an EVAP solenoid, which I also replaced. There's a V-shaped connector in that hose system—I replaced only the short segment leading to an unknown component (likely a valve or sensor), while leaving the longer hose intact. The hose returning to the throttle body and the large U-shaped hose running back to the fuel tank did not need replacement. The key takeaway: all hoses connect to a flexible, durable tube that doesn’t degrade over time—this makes it easier to maintain long-term EVAP integrity. I live in New Jersey (temperate climate). If you're in Florida, Arizona, or California, you may experience these hose cracks earlier due to heat and environmental exposure. To clear the codes after repairs: simply disconnect the negative battery cable. I removed it completely for safety and ease of access. After reassembling everything, I drove approximately 120 miles over four days (30 miles each way to work), and the check engine light has not come back on—great relief! Interestingly, the PO138 code disappeared after the EVAP repairs. While I originally planned to replace both oxygen sensors anyway due to age (93K miles), this fix allowed me to pass inspection temporarily without additional cost. I recommend purchasing all parts—including hoses, gas cap, and O2 sensors—from your Dodge dealership. As Jeff emphasizes, third-party stores like AutoZone may offer cheaper prices, but quality and compatibility matter—especially for emissions-related components. O2 sensors are not inexpensive, but they’re worth the investment. Overall, this repair took about 30 minutes of hands-on work at an intermediate skill level. A novice DIYer could complete it in under an hour with proper tools and guidance. Pro tip: Bring a sample of your existing hose to the dealership—they don’t carry part numbers for these custom-length hoses. I had them cut six feet of hose (about $50–$60) for all my needs. You won’t need 6 feet at once, but you’ll likely need enough material to cut into various lengths. I hope this helps others facing similar issues. Thanks again to Jeff and the community—your detailed posts make complex repairs accessible. I’m confident I saved money compared to a shop visit, and it’s reassuring knowing how much I can fix myself. I’ll share my O2 sensor replacement experience soon when I get around to it.

Related fault codes
P0138P0442P0455
Comments (2)
Anonymous 2010-04-30 05:03

Thanks for the kind words! This kind of detailed, practical content is exactly what helps others learn and save money. Great job sharing your experience with clear steps and real-world results.

Anonymous 2010-04-30 07:18

You're absolutely right—when people search online, they often look for specific codes combined with their vehicle model. I recommend updating the post title to include year, make, model, engine size, and OBD codes (e.g., '2003 Dodge Durango 5.9L - PO455, PO138, PO442'). This improves search visibility for future users. I’m curious about the PO138 code disappearance—while it’s common to replace O2 sensors at 93K, I’ve noticed a similar improvement in engine performance after EVAP repairs. My truck used to bog down significantly when driving in rain or on wet roads, especially under acceleration. Before this fix, hitting the gas would cause hesitation or even stalling. Now, it runs much smoother—especially in adverse weather. This suggests that clearing EVAP leaks can improve fuel delivery and engine responsiveness. It’s a subtle but noticeable improvement!