Quote:
Originally Posted by bsmith0404
I'm surprised it went into limp mode 3 times without throwing a code.
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Looking "literally" at the OP's first post, he indicates: "While going over mountain truck overheated three times. Temps going over 240 deg. Causing truck to go into limp mode."
He doesn't say that the truck "reduced power" or that he "had to pull over to the side of the road" or that "the check engine light illuminated" so, he may not have had a "computer induced limp mode" and may have just had the "check engine light come on". The Temperature gauges located in the instrument panel (one for transmission temp and one for engine temp) do not have any degree markings. They only indicate C H and a "normal range" between those letters. The only indication of actual temperature degrees is in the information display. In the "engine status" section, the engine oil temperature and the transmission temperature are indicated by the actual temperature of the fluid (oil or transmission fluid). An oil temperature of 240 degrees may (or may not) indicate an engine operating temperature but is, (I believe) the temperature of the oil as it exits the oil cooler on its way back to the engine from the secondary cooling system.
If the "check engine light came on, it may be for many "out of tolerance" indications, one of which is engine overheating but could be an EGT sensor problem, a voltage regulator problem or a host of other issues. The system "should" show a code if there was a malfunction, but may not show a code if the engine was within normal parameters and was "on the edge" of being outside the parameters.
One situation that occurred with me, during a hard climb up thte east face of Eisenhower tunnel was the DPF went into cleaning mode, the exhaust system was "on the edge of being too hot" because of the uphill towing conditions. On the other side of the hill, the check engine light momentarily came on as did the "CLEANING DPF" message. Shortly afterward, a "DPF MALFUNCTION" message appeared along with the check engine light (CEL). The CEL was still on when we pulled into the Ford dealership in Silverthorne. They checked the truck, no codes, the CEL was still on. Fortunately, one of the diesel techs remembered a TSB about DPF cleaning when in a "high performance mode" and said that the truck's computer will clear itself within the next two DPF cleaning cycles. Sure enough, climbing to the Eisenhower tunnel, the truck did a DPF regen, then again on the downhill side, it did another and all the lights went out, haven't come on again other than the normal "CLEANING DPF" message that appears momentarily when the cycle starts.
There have never been any codes stored, no indication of any "problem" other than the "check engine light" that was on until the DPF cycled enough times to clean itself. Afterwards, all is good.
I don't know for sure, but the OP's truck may not have gone into "limp mode" but rather the truck turbo protection system went into "altered fuel/timing performance" mode and the check engine light came on. This is a "normal sequence" if the EGT gets too high and is a design feature to protect the truck. Possibly, when he checked the oil temperature, it was 240 degrees... I don't know if "higher than normal" EGT temps that trigger an engine reduction are recorded as a "problem code" or not ????
Maybe he had a situation similar to mine? Then again, maybe not ???
Unless Ford can find a trouble code, pretty much all any of us can do is "long distance guess" on possible problems ??????
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