So just wanted to check to see if others have had this issue, or have recommendations. 98 XJ, 4.0, AW4. After a wheeling trip, I usually powerwash the undercarriage of my Jeep. (Especially after Moab to get that red dirt off). The last few times doing this, when I go to start the car, I get a crank no start. After letting it sit for a couple of hours, it starts and runs just fine. At first I thought it was because I was also washing the engine bay and getting the distributor wet, or water in the intake (cowl intake), but just the other day, I took it to a car wash instead of power-washing in my driveway and did not clean the engine, just the outside and undercarriage. It started just fine initially, and I left the car wash, and within a couple of blocks at a red light, it sputtered and stalled. It would start back up and idle normally for a couple of seconds, then sputter and stall on several tries. I got someone to pull me into a nearby parking lot, and I put my OBD2 scanner on it and got a couple of codes, most notably P0320. I checked the CPS connector, unplugged and plugged back in. It appeared to be dry. Couldn't find any loose connections. After about a half hour, I started it and it ran fine, so drove home.

What is it that I am getting wet that is causing this when I wash the vehicle? I wouldn't think the CPS itself getting wet would cause this type of a problem. I didn't remove it, so there is a possibility that the wiring is bad and it isn't the water, but the force applied with the pressure wash is causing a short, but wondering if anyone had any other opinions. I will be checking it closer this weekend for frayed wires and putting the multimeter on it to test the CPS, but wondering if there is something else I should be looking at. This is the only time I ever have a problem, so it has to be related to the power-washing in some way.

 

Ya I would check the wiring maybe the insulation is bad and water is shorting it out also try putting some dielectric grease in the CPS connector to help keep water out . but check the wiring because it runs close to the exhaust and the insulation can get hard and crack open and water can short it .

 

I've had that happen on numerous vehicles over the years.. You can wash it 5 times with no issues and then trouble on the 6th...lol... I hosed out a new crew cab work truck with the vinyl flooring and found the trans controller location with that washout... Went into limp mode until I got it dry..I usually cover the ECM and electronics on the jeep if I'm giving it a good washing... Heck I've had trouble with sealed connectors on a new Cat skidloader from powerwashing it...Just think about what you're doing before you do the job.. Now you know where one trouble spot is so take precautions for the next time...Let it dry, you'll be fine...

 

Right... I've washed this thing a hundred times with no issues, just recently started happening. I know a lot of people warn about power-washing the engine bay, but I have done it on all of my cars over the years with no issues. I'm just careful not to high-pressure the areas with electronics for the most part and have no problems. The connector itself was dry, it never got wet, so had to be in the wiring itself, or the sensor itself. Just never heard of a wet CPS causing it to go into limp mode. I think about all of the river crossings I have done without a problem, LOL!