Hi Scotty. I recently purchased a 2002 Dodge Ram B1500 Cargo Van with a V8 318 engine that has 161,000 kms. When it’s parked for awhile and the engine is cold, when I start it, it fires up, but runs rough. If I try to drive it cold, the van chugs with uneven power, and feels like it’s going to stall (feels like the engine is misfiring). But as soon as the engine warms up to around 120 degrees, it runs perfectly fine with no further issues. Every time I run it, I always have to let it idle until it warms up. One morning, when I was running it cold and it was acting up, I was giving it gas, and the check engine light came on. I hooked up my scanner and it came up with a single P0335 code (crankshaft position sensor malfunction). I checked out the sensor, and it looks brand new. Is it possible for a crankshaft position sensor to malfunction only when the engine is cold, but then work fine when it’s warmed up? Perhaps this new sensor is a faulty one? I look forward to your feedback. Thanks Scotty.
I should note that the temperature here is a high of 8 Celsius and a low of 3 Celsius on average with high humidity. Not sure if this has something to do with the Crankshift position sensor failing….I would think not, but……?
P0335 is not necessarily a bad sign, and may appear just cause you switched ignition on (in order to get the scanner connected), but did not start the engine: on an engine not started, the crankshaft position sensor cannot sense any crankshaft rotation cause there aint any.
As to rough idle at cold, it could be any of the three sensors: coolant temperature, engine temperature, or ambient air temperature. Their readings are being taken into consideration by the ECU when defining the injection parameters. If any of them is off, especially at cold temperatures you will notice that the engine is not running great. The bad thing is, that these sensors have a vast "grey zone": their readings can be way off, but the ECU may still not be able to notice that (and generate respective errors) before these readings become really and truly absurd.
/IMHO and based on my own experience, which may or may not apply to your specific car/
It's possible for anything to fail in the cold, the average lately has been 5°F & that turns any remnant moisture into possible problems if a component isn't sealed.
I'd give your battery a good cleaning & make sure the cables are tight first, then proceed with diagnosis.
Is your fast idle working by any chance? When mine has been rough in the morning for whatever reason generally the idle will kick up until it clears.
Everything you describe does indicate the crank shaft position sensor acting up when the engine is cold. I would try looking at live data with your scan tool for clues. If that doesn't pan out and the electrical connection looks OK, I would try replacing the sensor with an OEM part. If yours is an aftermarket replacement it could be the cause IMO. At worst you'll know what it isn't. Good luck.
I just received and installed a brand new OEM crankshaft position sensor ($30 from Amazon), and now the van runs perfect with the engine cold with no issues! Thanks for the response & feedback guys. Much appreciated.
Glad to hear it. You're welcome.