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2000 Plymouth Neon Check Engine Light: Codes 1654 and 0171 Explained

Model: 2000 Neon Fault Code: P0171 Posted: 2006-10-19 21:05

I recently purchased a 2000 Plymouth Neon with 103,800 miles and am experiencing a check engine light. The vehicle displays two diagnostic trouble codes: 1654 and 0171. Code 1654 indicates that the battery has been disconnected within the last 50 vehicle starts. I have since installed a new battery, which aligns with this code explanation. For code 0171 (Fuel Trim - System Too Rich), I’ve read that cleaning the Mass Air Flow (MAF) sensor may help. However, I need to clarify: does my 2000 Neon actually have a MAF sensor? The vehicle exhibits hesitation at idle, emits sooty exhaust, and leaves black residue on the ground beneath the tailpipe. I’m seeking advice on additional checks or potential causes—especially given that some sources suggest issues with the upstream oxygen sensor or EGR valve. Any guidance would be greatly appreciated.

Related fault codes
P0171
Comments (5)
Anonymous 2006-10-20 06:29

The 2000 Plymouth Neon does not have a Mass Air Flow (MAF) sensor. The issue may lie with the fuel pressure system instead. Check your fuel pump and fuel pressure regulator.

Anonymous 2006-10-20 07:41

Thanks for the clarification, Jeff! I’ll need to purchase a fuel pressure gauge. My Haynes manual lists a range of 44 to 55 psi—does that sound correct for this model? I’m looking to maintain proper fuel delivery and avoid engine performance issues. John

Anonymous 2006-10-20 16:02

Fuel pressure should typically be around 50 psi. Double-check the accuracy of your code 1654—some sources don’t list it, but according to the generic OBD-II code chart on this site, it specifically indicates a battery disconnection within the last 50 starts.

Anonymous 2006-10-20 17:26

Thanks for confirming 50 psi as the ideal pressure. I’ve verified that my 1654 code matches the description: the battery was disconnected in one of the last 50 starts. Since I installed a new battery within the past 20 starts, this explanation makes sense.

Anonymous 2006-10-21 06:20

Code 0171 could be caused by a faulty upstream oxygen sensor or an EGR valve issue—both are common in older Neon models. These components can contribute to rich fuel mixtures and the symptoms described, such as hesitation at idle and sooty exhaust.