1983 Chev G30 motor home 2012 LSI with a P1258 code
Perhaps someone can give me some clues as to what is going on relative to getting a P1258 code. This is an over-temp code and the problem is that I get this code with a cold engine. Checked the wiring, (this is an engine swap) replaced the sensor with OEM component, (I did not remove the old sensor just plugged the new one and allowed to hang at room temperature), no change. Other than random misfires, get that code also, (engine is in limp mode, cylinders turned off to limit heat), and the exhaust is not completely hooked up, I am at a point of looking elsewhere. The engine harness is from the donor vehicle, I have read that some GM engines had another sensor to detect an overheating situation but if there, can't find it. Dakota gages (VHX) are displaying normal temp off the engine data stream, climbs with engine run time. Engine temperature is normal, when running for an extended time, have never experienced an overheating situation. Would run until thermostat would open. The computer is also from the donor vehicle and all indications is that it is good. Does this sound like a computer problem? The fact that the gage (Dakota VHX) is reading the correct value is telling me that the value in the OBD2 data stream is normal, making me start to look at an internal problem with the computer. Exhaust from the engine doesn't indicate anything sinister. The other clue is this condition doesn't give me a check engine light. Scan tool and the misfiring are my detectors.
Anyone have other suggestions??
Russ C
