Facing a frustrating smog test failure with your 1996 Plymouth Voyager? You’re not alone. Many owners of older vehicles, like the classic Plymouth Voyager, run into snags when it comes to emissions testing, especially concerning the OBD2 system. Let’s break down what those OBD2 “emissions status” lights mean and how they relate to passing your smog check, specifically for your 1996 Plymouth Voyager.
Your OBD2 system typically uses three indicator lights: green, yellow, and red. These lights are designed to give you a quick visual status of your vehicle’s emissions systems. After clearing fault codes, you might initially see a yellow light. The good news is if you’re now seeing a green light, it indicates progress, but does it guarantee a smog test pass for your 1996 Plymouth Voyager? Not necessarily.
The core issue you’re experiencing, “incomplete monitors,” is a common hurdle. These monitors are self-tests performed by your Plymouth Voyager’s computer modules (CMs) to ensure all emissions systems are functioning correctly. For a vehicle to pass a smog test, these monitors need to be in a “ready” state, meaning they have completed their tests. You mentioned needing only one more monitor to complete out of five or six.
Disconnecting the battery, a common practice during car maintenance, often resets these monitors to an “not ready” state. This is why you were advised to drive your 1996 Plymouth Voyager to retrain the CMs. The driving cycle is crucial for allowing the car’s computer to run all the necessary diagnostic checks. Driving 250 miles with a fuel tank level between 30% and 70% should, in theory, be sufficient to complete these monitors. However, as you’ve found, this isn’t always the case. Multiple trips back to the garage revealing “incomplete monitors” suggest a deeper issue.
The appearance of the “check engine light” and the P1698 fault code points towards a communication problem. P1698 often indicates a communication failure between the Transmission Control Module (TCM) and the system bus, or potentially between different CMs. While your OBD2 reader also showed a P0300 “random misfire” code, the P1698 is particularly relevant to system communication and monitor readiness. Erasing these codes, while turning off the check engine light, also unfortunately resets the monitors again, putting you back at square one with the driving cycle.
It’s worth considering the information found in online forums regarding Chrysler minivans and P1698 codes. These discussions often highlight that a P1698 doesn’t always mean the CMs themselves are faulty. Damaged wiring or cracked solder joints can disrupt communication and trigger this code. This could be a plausible explanation for your 1996 Plymouth Voyager, especially given its age.
Before diving into potentially complex wiring inspections, consider the possibility that the issue might be simpler. There are reports suggesting that sometimes the CMs in older Chrysler minivans, like your Voyager, can be problematic when it comes to being scanned by emissions testing equipment. This could lead to false “incomplete monitor” readings even when the systems are actually ready.
Your mention of intermittent electrical issues, such as wipers spontaneously activating and the transmission going into limp mode, could be related to the broader electrical system health and potentially the CM bus. These symptoms might reinforce the idea of a wiring or solder joint issue affecting communication within the vehicle’s computer network.
To move forward, while inspecting wiring might seem daunting and involve battery disconnection, it could be a necessary step. Given the age of your 1996 Plymouth Voyager and the persistent “incomplete monitors” along with the P1698 code, addressing potential wiring or solder joint problems could be the key to finally passing your smog test. Consider a systematic approach to checking wiring harnesses and connections related to the PCM and TCM to rule out these common culprits.
