CrisostamoSH90

Hey everyone,

I have an 03 wj with the 4.0 automatic 162,000 miles young. I have a few codes need some direction in. First is the P1756, from what I understand I should just go ahead and replace the tranny pressure solenoid/switch/sensor. The others are P1195 and P1196. Slow bank 1sensor 1 and bank 2 sensor 1 slow during cat monitor. Need some help with diagnosing the fix.

Any help would be appreciated,
Thanks,
Nick

dave1123

First of all, replace both 02 sensors. My 2000 4.0 doesn't have downstream sensors, IDK if yours does or not.

The trans problem is probably the governor pressure solenoid. It could be the governor pressure sensor, but that seems to be detecting pressure so I'm leaning toward the solenoid being the culprit. The only real way to tell is to check governor pressure at the test port. With the vehicle up on the lift running in drive, wheels stopped, the pressure should be 0 to 1.5 psi and should increase 1 psi for every 1 mph as it accelerates. The solenoid is a pulse-modulated unit controlled by the TCM.

CrisostamoSH90

Will do, I was leaning towards that but wasn't a fan of just throwing parts at it. Seems like that's the best option to replace both O2 sensors. I believe I have the CA em mission so I think I have 4 sensors. But I'm not sure, it's never on my mind to count when I'm under the jeep.

As far as the governor solenoid goes, does anyone have a part number so I can order a replacement? I'll probably just replace the sensor and solenoid at the same time. I don't want to replace one and have to drop the pan again to replace the other. Thanks for your help Dave.

Nick

dave1123

My 2000 4.0 has CA emissions as well and only has 2, but your 2003 might be different. Mine only has the 2 pre-cats on the manifold pipes and a round can just before the muffler. I can't find anything else.

CrisostamoSH90

thanks Dave, I will have to go out and check just out of curiousity when its not raining. In any event we know its the "upstream" sensors.

As far as the transmission issue goes, 125 views and not one person (besides Dave) has any input on it, whether it be a part number, link, or even a "yes sounds like the solenoid"?

Thanks for all your help Dave,
Nick

dave1123

Well, you know, some people you have to smack in the head with a 2x4 to get their attention! LOL!

Seriously though, a lot of people don't want to get involved with transmission stuff. I know just about enough to make me dangerous. I've rebuilt several GM transmissions in self defense, but never had a 42re apart. I bought the FSM for it though. I actually took the time to review it before I answered your post. But, that's the kind of guy I am.

BTW, you can download the Full Service Manual for your specific jeep at pacificcoastmanuals.com for $7.99 + tax. It's 93MB of pdf files and well worth the price. There's about 140 pages just on the transmission.

CrisostamoSH90

Not to resurrect my own lost, but what brand do you guys recommend for a sensor? It completely slipped my mind I was due for a state inspection, but the boys in blue remember everything. Rockauto has me between NTK and Denso. Denso is cheaper which I like. She's an old girl so I'm just trying to pass my inspection

Thanks all,
Nick

dave1123

Denso is a reliable product. I replaced mine with Bosch because they came with the harness plug already wired. IDK about Denso. They were, at one time, a supplier of parts for Chrysler's production lines.

In JEEP years, your 03 isn't that old. My old gal is like a grandmother that runs marathons! 190K and still going strong. Oil is clean every time I change it (5K), good pressure anytime, trans is perfect except for being a little reluctant to function on really cold startup. I'm in the habit of letting it warm up for a couple of minutes in Neutral before starting out in the morning. One thing I'm going to warn you about. DO NOT use the shifter to stop a reverse roll. It puts way too much stress on the forward clutch.

This is probably the newest jeep I'll ever own. I can still figure out the electronics in this!

CrisostamoSH90

Thanks Dave, I'm thinking I'll go with Bosch too. It's actually a cheaper option. My 03 is tired. Lifters tick and the tranny is still an issue. I guess I can't complain. I've gone probably 10,000 since the last oil change. She tired of old oil and new oil seems to make her louder. Thanks for the info.

Nick

dave1123

IDK how much you know about jeeps, but lifter tick is standard issue with the 4.0 and has been since the beginning. As long as it disappears above about 1500 RPM, don't worry about it.

One thing I'm curious about. According to wjjeeps.com, there was running change in the 2002-2003 models where they replaced the oil pressure sensor with a simple switch that would show 40 psi on the gauge and never anything else. My 2000 unit went and I got one from Napa and that's all it did. I got a Mopar one from my dealer and it showed real pressure. I asked the parts guy why Chrysler didn't just go to an idiot light and he said they thought it would cut into sales!

SO, if you need to replace yours, get a Mopar unit for a 2000-2001.

My 4.0 had 190K on it and I'm using 10W-30 semi-synthetic oil. I run 5K on changes and don't do a lot of short trips. I use it for newspaper delivery 3 days a week and it's running constantly for about 3 to 4 hours every time. The oil is still perfectly clean after 2K and it's hard to get a reading because it's so clean. I'm running 50 psi on cold startup and 40 psi at idle hot.