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2005 Chrysler Town & Country P1684, P0562, and P0420 Codes: Diagnosis and Fixes

Model: 2005 Town and Country Fault Code: P0420 Posted: 2014-02-21 21:05

I own a 2005 Chrysler Town & Country that has been displaying three check engine light codes: P1684, P0562, and P0420. Based on other forum posts, I believe P0562 may indicate a low system voltage issue, possibly related to the battery or charging system. The P0420 code points to catalytic converter efficiency below threshold (Bank 1), which could be due to exhaust system performance issues. I've tried using sea foam in the exhaust, but it hasn't resolved the problem. I'm unsure what exactly the P1684 code means and would appreciate any expert insights or troubleshooting steps for these codes. Any advice on how to diagnose and fix all three codes would be greatly appreciated.

Related fault codes
P0420P0562P1684
Comments (5)
Anonymous 2014-02-22 08:19

P1684 = Battery disconnected within the last 50 vehicle starts (per Chrysler documentation). P0562 = System voltage is below normal levels. P0420 = Catalytic converter efficiency is below expected threshold for Bank 1. First, inspect the battery condition, charging system, and all terminal connections. Resolving the first two codes may help address or eliminate the P0420 issue.

Anonymous 2015-03-29 20:50

My 2005 Grand Caravan (same model year) has experienced a P0420 code at around 184,000 miles. The front oxygen sensor readings appear normal but fluctuate, while the rear monitor reads consistently high (1.3V) with little variation. I notice oil consumption of about one quart every 1500 miles—no visible leaks—and the tailpipe shows black carbon deposits. Could excessive oil be overwhelming the catalytic converter? I added a pint of Lucas fuel system cleaner to a full tank, and after using half the tank, the MIL light turned off—but returned after the next refill. Any insights on this would be helpful.

Anonymous 2015-03-30 07:41

Use an OBD2 scanner to monitor ECT (Engine Coolant Temperature) and exhaust temperature sensors. Compare pre-cat and post-cat sensor readings graphically to identify any anomalies. A rear oxygen sensor reading of 1.3V is unusually high—please confirm all codes being reported, as this may indicate a deeper issue.

Anonymous 2017-09-20 12:26

I recently fixed the P0420 code on my 2005 Dodge Grand Caravan this weekend. The solution involved replacing the downstream oxygen sensor and installing a check engine light eliminator adapter (cost approximately $30 total). For reference, here's a YouTube video showing the process: https://www.youtube.com/watch?v=qkhDeOvvvX0&t=324s

Anonymous 2017-09-20 13:35

It’s important to note that simply eliminating sensor readings—such as by using an adapter—does not fix the underlying issue. Instead, it masks faulty data and may lead to unsafe driving conditions. While this might temporarily clear the check engine light, it does not resolve the root cause of poor catalytic converter performance or potential emissions violations. Always ensure any repair addresses actual hardware faults before relying on software-based fixes.