Sensor Circuit Low Codes
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Sensor Circuit Low Codes
I recently started getting these codes on my 06 F350:
4072 - Exhaust Back Press. Sensor Circuit Low
0405 - EGR Control Circuit Sensor A Circuit Low
2285 - Injector Control Pressure Sensor Circuit Low
I just replaced the EBP and ICP sensor and cleared codes and drove it down the road and they came up again. Truck is parked during the week and driven on weekends and some times the first day I drive it, either it will just shut off, and restart with no promblems and be good the rest of the weekend or if I run down the interstate its like it goes into passing gear and turbo boost jumps up to 25+ psi and truck loses power and turbo farts any time I let off the throttle. I either pull over and shut it down and resart it and promblem goes away or just baby the throttle and ride it out. Anyone experience anything like this or have any ideas on things to check.
4072 - Exhaust Back Press. Sensor Circuit Low
0405 - EGR Control Circuit Sensor A Circuit Low
2285 - Injector Control Pressure Sensor Circuit Low
I just replaced the EBP and ICP sensor and cleared codes and drove it down the road and they came up again. Truck is parked during the week and driven on weekends and some times the first day I drive it, either it will just shut off, and restart with no promblems and be good the rest of the weekend or if I run down the interstate its like it goes into passing gear and turbo boost jumps up to 25+ psi and truck loses power and turbo farts any time I let off the throttle. I either pull over and shut it down and resart it and promblem goes away or just baby the throttle and ride it out. Anyone experience anything like this or have any ideas on things to check.
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I did the pigtail, I just find it strange that all codes are because a low circuit. I just had the dealer replace three injectors and they replaced a wire harness (something for the injectors) but this started about a week or two after I got my truck back, I guess I'll have to run it back up there and see what they come up with. Thanks
Lead Driver
Joined: Sep 2007
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From: Scio, OR
I've attached a wiring diagram below. Notice how the three sensors you are getting codes for work. They take a line (VREF) from the PCM and vary it with another line from the PCM (SIG RET) and return that signal back to the PCM.
VREF is a regulated +5V. SIG RET is ground. So the third wire coming from the sensor varies between +5V and ground, depending on the pressure (ICP and EBP) or position (EGR).
Now the problem is if VREF is less than +5 volts for some reason, the PCM gets back a signal out of range and reports a code.
Use the diagram for the ICP sensor and check the VREF pin (labeled "reference voltage", pin 2) with a digital volt meter. It should be nearly exactly +5V. It might be +4.9 or something similar, but it should be right in there. If it isn't, you probably have a VREF wire chafing and partially shorted to ground.
Edit: William beat me to it.
VREF is a regulated +5V. SIG RET is ground. So the third wire coming from the sensor varies between +5V and ground, depending on the pressure (ICP and EBP) or position (EGR).
Now the problem is if VREF is less than +5 volts for some reason, the PCM gets back a signal out of range and reports a code.
Use the diagram for the ICP sensor and check the VREF pin (labeled "reference voltage", pin 2) with a digital volt meter. It should be nearly exactly +5V. It might be +4.9 or something similar, but it should be right in there. If it isn't, you probably have a VREF wire chafing and partially shorted to ground.
Edit: William beat me to it.
Fleet Owner
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I would also disconnect the EGR valve (when the engine is off and cold), clear the codes, then run it and see if they come back. William and David have you on the right track w/ the vRef IMO. The vRef issue can be internal to a sensor also - at least as I undersatnd it.
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Thanks for the help, I'll pop the hood and see if I can find anything on the wires. Drove the truck a good part of the day and I got a 0299 code (turbo/supercharger underboost) do think that is caused by my sensor issues?
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