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good afternoon my name is ***** ***** I will assist
the white smoke is an indicator of coolant in the combustion chambers. it will also cause the missfire
the codes are related to the egr failure. when you cleaned the egr, was the coolant present???
no coolant in egr port
both codes indicate that the egr is the issue. sometimes you do not see the coolant but it may be there. the white smoke is a confirmation.
I run engine until I got it to miss. I removed egr valve and pressured cooling system for 4 hours and have no sign of coolant in the intake. the smoke has a gray tent to it
Hi there. Different expert here.
The codes you mention point to a problem with the return signal turn circuit from the EGR throttle position sensor to the PCM; P0407 indicates signal voltage too low, while P0488 indicates signal voltage out of range - basically, what these codes are telling us is that the return signal voltage is actually lower than what the parameter allows.
For the cause of these codes, we should look first at the condition of the throttle body. Carbon and/or oil deposits can cause the throttle plate actuator to fail causing driveability problems. So first step should be to make sure the throttle body plate is clean and free to be opened and closed by the actuator.
If the throttle plate was found to be clean and operating correctly, then our second step would be to test the position sensor signal voltages - best way to do this would be with a VCM loaded with IDS software, but we could also use either a good DMM or a scope. Have any of those available?
trottle plate is clean besides a little oil film. How can I tell if trottle plate is operating correctly?
We can assume is operating correctly if the plate is clean and there are no signs of binding on the throttle bore.
I have a snap on modis. Is this suitable for the test? If so , can you explain the procedure? i also have mulimeter
I'm not familiar with the snap on modis, but we can perform the tests with the multimeter. Just give me a few minutes to dig up the wiring diag. Hang in there...
Hey, just curious, can that modis read this kind of PID's? If yes, it would make both our jobs a lot easier....
which pids you need. I can check the data screen
Well, for PIDs, we'd like to see EGRTP position return signal; for actuator tests, I'd like to be able to command the EGRTP actuator OPEN and CLOSED. Can it do that?
I don't mean to blow your mind or anything (heck, mine is already blown, we sure don't need another casualty ;-), but I wanted you to have an idea of what we're trying to diagnose, so I've attached a document describing the system and what causes it to set code P0488.
Did I loose you? Anything on that PID or actuator test? Can your multimeter ot the modis read frequency (Hz)? If not, then all we can basically do is check for VREF voltage and return signal at the EGRTP position sensor:
VREF (Brown/White wire) should be between 4.5 and 4.9 volts
Return signal (Light Blue/Orange wire) should be less than 1 volt with the plate closed and increase to more than 4.4 volts with the plate wide open.
Please let me know if you'd like to continue this diagnosis, if not, please tell me so.