SES light and "limp mode"?

[BigGreen7.3Machine]

The past few mornings (30,40,50 degrees) I have gone out and started my truck before headin to work and it runs normal. Hop back in 10 minutes later still fine. Start driving, everything still normal and than all of a sudden the SES light comes on and my truck goes into a sort of "limp mode" runs like absolute crap almost wants to die at idle, and shifts late. I pull off the road, turn the truck off, turn it back on and it runs fine, no SES light, start driving again, fine for a 1/2 mile and then repeat. Does this all the way to work. Then after my shift (truck sitting roughly 5hours) and it has been fine. No problems for the rest of the day. Has this happened to anyone?! This is my daily driver and I cant have it be down! All help appreciated!


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[NoRalPh]

You have a bad sensor... Kinda hard to guess though, and they're too expensive to just try and see See if you can find somebody with the right scanner (Unfortunately, it takes a special scanner to retrieve them, the Generic ones the Parts Stores use aren't any good). Try a local shop, the professional scanners work, Or, maybe go to the Hometown Forums here (at the bottom) and post something in the Iowa forum asking if somebody close to you has an AutoEnginuity.

[BigGreen7.3Machine]

Any clues on what sensors or modules I should be looking at?


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[scagle1]

ICP sensor , but as previously stated it would be beneficial to get it scanned and watch values as $200 is a lot to spend and be wrong on a hunch

[BigGreen7.3Machine]

Newbie question but what exactly does the icp sensor do? And are there any testing procedures?


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[scagle1]

ICP = injector control pressure, sends a signal to the IPR regulating the pressure or asking for more. Try disconnecting the ICP , should put it into a default mode when running. Truck will run fine but not as well as with a functioning ICP, if it cleans up lopey idle, miss feeling then most likely your ICP is bad. Check for oil in the connection, it is a sign of a failing or failed ICP, getting it hooked up to a computer and getting some values of ICP, ICP volts and duty cycle would be idea tho.

[BigGreen7.3Machine]

So it happened again this morning and I'm afraid it's going to keep this up, I need to get it figured out and fixed as I have a pretty long road trip coming up here end of the month. My ICP sensor was leaking oil through the connector so I went ahead and replaced it a few days ago, definitely made the truck run a little better but stil have the intermittent limp mode / SES light condition. Does it multiple times in the morning till fully warmed up and then doesn't do it for the rest of the day!

[timmyboy76]

Originally Posted by BigGreen7.3Machine

. Does it multiple times in the morning till fully warmed up and then doesn't do it for the rest of the day!

Starting to think, its the EBPV. There's a sensor at the bottom of the turbo pedestal. If bad/get'n wrong info, it'll close the valve. Unplug it and see what happens. Also, may want to check this too..


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[BigGreen7.3Machine]

Would this cause a SES light and the truck to go I to "limp" mode though? Like motor shaking bad/ running really rough? Then turning it off/on and being fine again? I cleaned the EBP sensor and tube at the same time as the ICP replacement this last saturday

[timmyboy76]

it can. The valve blocksthe flow of exhaust. Does your truck, in the morning, idle up? If so, does it make a jet-type engine sound? When your trucks falls on its face, does it make the same sound?

Possible also, you got a loose UVCH connector. May want to pull the valve covers and inspect the plugs under the vc, see if its loose. If so, look up the 50 cent mod...