What does the Diagnostic error code P1698 on a 1998 plymouth voyager mean, and how can I locate the part and change it?

ECM electronic control module not working may be a loose wire or bad ground

okay, 1998 voyager these are not obd2 codes, these are genric codes, you used ignition to get these .
these codes are for older models that use codes like these 12 35.
the newwer obd 2 use codes like po 013. i will try to see what i can find, also the engine size is important.

okay here we go, the first code is 12, this code means the battery was dead or dissconnected.
the next code 35. this code means loss of prime, code # 11
means internal transmission failure.
the code 55 means gear ratio error.

these codes would tell me that you have transmission problems. this may mean internal trans failure and a rebuild or replacement transmission is needed or shift pack needs replacing. anyhow i would have a shop check this out, these van are known for transmission problems. hope this is helpful good day

Thanks for choosing FixYa and welcome to the site. It is located above your brake pedal and gas pedal. This is where they hook up to read codes at.

According to the manual

P0134= Right Rear (or just) Upstream O2S Stays at Center

Discription=Neither rich or lean condition detected from the oxygen sensor.

P0401 =EGR System Failure

Discription= Required change in air/fuel ratio not detected during diagnostic test.

hope this helps

Code 1491 on Plymouth Voyager is Radiator fan not working, Check wire fitting to be tight, Check fuse and fan relay could be bad swap out the relay to another relay many of these are the same #

Instrument panels are computers in them selves. it could have blown. check fuses and have it put on a diagnostic scanner and checked for any codes

I have tow of the three requested codes. po300 is misfire detected at multiple cylinders. See po301-306 represent the cylinder # misfire. So 301 is cylinder #1 misfire.

po420 is Catalytic Converter Efficiency Failure

According to minimopar.knizefamily.net, fault code 31 is "Purge Canister/EGR Solenoid".

You need to have your charging system alternator, connections etc, checked if battery keeps dying. Are you sure it code P50 your getting?

The code refers to the leak detection pump that is part of the gasoline vapor control system which is for pollution minimization. It says either that the pump switch or mechanical operation is faulty. I had this happen on a 2000 Dodge Dakota and a replacement Gas Cap fixed the problem. A faulty gas cap seal can also cause this.

Good luck