Engine/Transmission (1998.5 - 2002) Gremlins? Check engine light on/off

[DaveN]

I was out "playing around" friday night and ended up driving the truck through a couple of mud puddles. Nothing really severe (maybe 4~5" deep tops) and didn't think much of it. About five miles down the road my shift points were basically random, sometimes the truck would shift at 1000 rpm, sometimes 3200, it was constantly upshifting and downshifting - hunting for a gear. Also it seemed like I had reduced power (maybe 70%). I drove it home figured I'd get to it in the morning. No check engine lights came up.



Next day I started it up and took it for a drive, drove great. No problems. Figured something got wet, and it dried out overnight. So I went to Home Depot to pick up some stuff. On the way there I leave a light, get up to about 25 mph, and the throttle doesn't work. I've got it mashed to the floor, and I'm at idle. This lasts for about 20 seconds, then the check engine light comes on, and the truck seems to start running ok again. Get to Home Depot, and I leave the truck idling in front of the door (I was afraid to shut it off). As I'm waiting for my friend to come back out, I'm watching my tach vary from about 800~1200 RPM all by itself. So we load up the truck and head home. Drove OK, but it felt like the throttle was not constant, it seemed to vary (like in the parking lot).



So we do our home repairs, and I get ready to leave. Start the truck up, the check engine light DOESN'T come on (I thought they were supposed to stay on until the dealer reset them?) and the truck drives fine for the next 150 miles.



I'm thinking something got wet and dried out, any ideas? I could understand this kind of problem had I really went through a lot of water, but I don't think anything really got that wet under the hood. Since the check engine light went out, does the ECM still hold the error code? Thoughts on how to proceed?

 

[PCrable]

The problem you're having with the pedal down and the engine still running at idle would likely be a problem with your Throttle Position Sensor (TPS) / Accelerator Pedal Position Sensor (APPS) . When it has problems, it will set a fault code in the computer and the check engine light will come on. The check engine light will go off if the same problem doesn't come back within 3 (I think) off/on cycles of the engine, but the fault code will still be stored. You can take it to an AutoZone store and they can read the fault codes for you for free.



Start there and keep us updated...



--Phil

 

[DaveN]

Well seems to be running OK now, I ended up with code P1693, which is "DTC detected in companion Module" or "DTC detected in PCM/ECM". Not sure what a DTC is... ... . hopefully that translates to "something got wet. "



I'd like to know what it was, I'd hate to hit a puddle in the street and have the truck stop on me, maybe it's something I could seal up a little better?

 

[Sean Flanagan]

DTC Stands for Diagnostic Trouble Code ( I think). The companion module is probably the PCM (Power Train Control Module) which is the one controlling the transmission.



Hi Phil,



Did you get yours fixed ok?

 

[PCrable]

Hey Sean,

$362 and about 15 minutes of work later, I'm working fine again.



Now if I can get my Horton fan fixed up and the Fuel Tank Sending Unit changed out...



--Phil