What does code P1899 mean on my Plymouth Neon, and why won't it start?

Short answer: P1899 is a Chrysler code for the park/neutral switch circuit. That's the switch on the automatic transaxle that tells the computer the car is in Park or Neutral, so it's allowed to crank. The computer also needs it to allow torque converter lockup. If the car won't crank in Park but will in Neutral, suspect the switch or its wiring. But one Neon owner found the code came from a cut wire higher in the harness, and his no-start was actually a bad starter.

Symptom: A check engine light with P1899, the car won't crank in Park (but sometimes will in Neutral), just a click when you turn the key, or odd idle or shifting behavior.

What to check first

1. Try starting in Neutral with your foot on the brake. If it cranks in Neutral but not Park, the park/neutral switch or its adjustment is suspect.
2. Look under the car at the switch and its connector on the transaxle. Owners mention curb or road damage there.
3. Follow the wiring up from the switch. One owner's P1899 came from a damaged wire higher in the harness.
4. Have the battery and starter tested if it clicks or does nothing in both Park and Neutral.

Likely causes

1. Faulty park/neutral switch or shift cable adjustment. The switch sits low on the transaxle and can fail or get damaged. A loose or misadjusted shift linkage can cause the same code.
2. Damaged wire or connector in the switch circuit. A new switch didn't clear one owner's code. A cut wire higher up did.
3. Bad starter or weak battery (for no-start). The same owner's no-start turned out to be the starter, not the switch.

What it usually costs

Owners in these threads didn't post prices. The switch is a small part, and wiring repairs are mostly labor. Test the starter and battery before buying parts.

Is it safe to keep driving?

If it starts and drives normally, you can drive it while you sort out the code, but a bad switch can leave you unable to start. Never bypass the park/neutral switch. It's what keeps the car from starting in gear. Verify with a mechanic.

DIY or shop?

DIY-friendly for checking the connector, wiring and switch if you can get under the car safely. Shop for starter testing if you're not equipped.

Recalls, bulletins and complaints in plain words

• No recall covers the park/neutral switch on the 1995–1999 Plymouth Neon in NHTSA's recall data. Run your VIN for other open recalls.
• NHTSA complaints: 79 keyword-matched complaints for Plymouth Neon 1995–1999 (of 1,199 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-20; keywords: neutral safety, park/neutral, park neutral, won.?t start, no start, not start, starter, crank, shift, transmission).

What owners report

• In 1998 Plymouth Neon P1899 Code on Car Talk, a 1998 Neon owner with a 3-speed automatic got P1899 after a long list of other repairs. Members said it's the park/neutral switch circuit and can cause erratic torque converter lockup (surging). They said to look for curb damage, since the wiring sits low, and to check the shift linkage adjustment. The computer won't allow converter lockup unless it sees the car out of Park or Neutral. A new switch didn't clear the code, which came back at 55 mph.
• In 1998 Plymouth Neon Starting Problem on Car Talk, the same owner followed up. His intermittent no-start, with a screech or no crank at all, turned out to be a defective new starter. A member said P1899 is almost always the wiring, switch, installation or shift cable, not the computer. The P1899 came from a wire that had been cut higher up and hidden in the harness.
• In 2000 Dodge Neon - What next? on Car Talk, a Neon owner had a no-crank even after a new battery, starter, cables and ignition switch. Members suggested checking voltage at the battery and starter and trying to start it in Neutral to test the park/neutral switch. Another added that a failing switch doesn't always work in Neutral either.

My take

My advice as a former lot tech: when an old automatic won't crank, the first thing I do is put it in Neutral and try again. It's free, and it tells you whether to look at the switch or the starter.

Vehicle focus: 1995–1999 Plymouth Neon with the automatic transaxle (the Dodge Neon is the same car).

Safety / mechanic note

Never bypass the park/neutral switch; it prevents starting in gear. Verify with a mechanic.