I have a 2006 6.0 with 86,000 miles and my wrench light comes on when I am pulling a heavier load. (5-10k) It has done it about 4 times in the past 6 months. As soon as it comes on the truck loses power and I have to pull off to side of road and shut off truck to reset. What is going on?? Have not seen any codes with this problem. Also my engine light came on a couple times with the P2099 code saying I have an underboost condition. Do I (or should I) take it to ford and let them tell me whats wrong or am I better off going to an independent diesel shop? Thanks for any help

Jared

 

Can you read live time data from your engine ? Scangage 2 or dash boss?

 

The most common reasons for a wrench and low power that returns after parking the truck for awhile are a plugging oil cooler and a sticking turbo (overboost). Get some gauges as mentioned above.

 

A P0234 turbo overboost will set a wrench light and PCM de-rate. A P0299 turbo underboost won't.

 

Thanks Mike. My thinking is that he might not be able to read all the codes and might miss seeing a P0234 code. For some reason some code readers can only pull down partial info - especially wrench light codes. Could be wrong, but that was my thinking.

The P0299 can come from a number of sources actually, so the key is to get a gauge system (scan tool) so he can monitor the engine parameters to narrow it down.

I agree that when a P0299 is actually a turbo issue, you will probably get other codes with it.

 

Yep oil cooler. Happened to me this summer.

 

Been there, done that! Customers truck, by itself, no issues. Put a large weight behind it, on a hill, gradually loses speed. After the second downshift, wrench light comes on, and its like his foot slipped off the accellerator. Pull over, shut it off, restart it, runs fine, no wrench light. Only code.....p0299. VVT test is normal, turbo boost test normal. EGR valve test normal. ECT and EOT 5-8 degrees within each other.

 

I understand the "underboost" part of the impact from low fuel pressure (or a bad pump). I guess it is the wrench light piece that is surprising.

Does Ford have any good resource guides for you that help you track down issues like this surprising wrench light, or is it just up to the customer to be sure and take the truck to a talented Tech??

Thanks Vince.

 

It will just "think" that its underboosting. Boost at the time of shutdown....right at 30.
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Signal Functions The variable geometry turbocharger (VGT) is controlled by the powertrain control module (PCM). The PCM uses an exhaust pressure (EP) sensor to monitor the pressure and adjust the VGT solenoid duty cycle. The VGT solenoid receives a pulse width modulated (PWM) signal from the PCM that controls the solenoid on/off time. The VGT solenoid directs oil to a piston within the actuator housing. The direction of oil flow to the piston increases or decreases the exhaust pressure.

Sensor Bias The VGT solenoid control is based on input sensors. The input sensors are used to calculate the engine speed, desired fuel quantity, altitude, and exhaust pressure. The amount of voltage the sensor deviates from a calculated reference value (sensor bias) may cause a commanded versus actual pressure calculation error.

Detection/Management The PCM monitors the exhaust pressure. A DTC is set when the difference between the commanded and the actual exhaust pressure is not within the calibrated limits.

 

I thought that the wrench light was "triggered" by specific conditions that also de-rated the engine. Instead, is it correct to say that the wrench light will come on in most de-rate conditions?

 

Mine never derated anything. Light come on, engine fan run all the time. I was told when the coolant and engine oil get so many degrees apart the light comes on. Only came on for me when hot out and working the truck. Might have de rated if I left it longer maybe.

 

That is another "derate" situation. This one didnt have a temperature differential out of range.

 

Not necessarily. This instance had a trans range sensor, load, speed, "turbo" issue.

 

Ford just didn't make troubleshooting easy did they - lol.

Hats off to you Techs!!!

Thanks Vince.

 

Did I mention I'm losing my hair?