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Check Engine Light but No Codes


ford2688
02-12-2019, 02:55 PM
Hi,
Check Engine Light came on. 2009 Ford Explorer 4.0 xlt
Code reader turns up NO Codes, it just cycles through showing dashes (----) but no letter or numbers and will not reset.
I also notice that the Average MPG seems to be stuck around 16.5 mpg no matter the driving condition. I know the mpg would change while driving, but this rarely moves.
Any ideas???
Thanks,
Angelo

65comet
02-12-2019, 06:02 PM
Sometimes a low voltage condition will cause all kinds of extra or phantom codes. Take it to an auto parts store and see if their code reader comes up with anything. If not, then ask them to check the voltage of the battery and the alternator.

ford2688
02-12-2019, 07:34 PM
Sometimes a low voltage condition will cause all kinds of extra or phantom codes. Take it to an auto parts store and see if their code reader comes up with anything. If not, then ask them to check the voltage of the battery and the alternator.

If the weather is a little better tomorrow I'll do that.
Thanks,
Angelo

shorod
02-13-2019, 02:17 PM
I also notice that the Average MPG seems to be stuck around 16.5 mpg no matter the driving condition. I know the mpg would change while driving, but this rarely moves.


How long has it been since the Average MPG was reset? The display does exactly what it says, it averages over the MPG from the last time it was reset. If it hasn't been reset for hundreds or thousands of miles, even large changes for a short duration will have very little impact on the overall average.


As for only dashes being shown when checking for diagnostic codes, are you referring to dashes on the diagnostic tool's display or on the display in the Explorer's instrument cluster? Have you ever successfully pulled diagnostic codes from this Explorer using the same diagnostic tool?


-Rod

ford2688
02-13-2019, 04:42 PM
How long has it been since the Average MPG was reset? The display does exactly what it says, it averages over the MPG from the last time it was reset. If it hasn't been reset for hundreds or thousands of miles, even large changes for a short duration will have very little impact on the overall average.


As for only dashes being shown when checking for diagnostic codes, are you referring to dashes on the diagnostic tool's display or on the display in the Explorer's instrument cluster? Have you ever successfully pulled diagnostic codes from this Explorer using the same diagnostic tool?


-Rod
I never used this reader on this truck. The dashes were in the code reader.
I'll be back home tomorrow and look at it. Maybe disconnect the battery to reset?
Angelo

ford2688
02-14-2019, 02:31 PM
Today I just went ahead and disconnected the negative battery terminal for about an hour.
Connected and started and there is NO CHECK ENG. LIGHT.
If it IS going to come back on, how long, or how many miles will that take??
Angelo

65comet
02-14-2019, 05:39 PM
If the problem doesn't cause an immediate code, usually 60 miles is needed for it to go through all its checks and come up with a firm "things are OK".

ford2688
02-21-2019, 05:40 PM
If the problem doesn't cause an immediate code, usually 60 miles is needed for it to go through all its checks and come up with a firm "things are OK".
Hi,
I disconnected the battery and reset the engine light.
After about 65 mi. the light came back on.
Advance Auto pluged in and came up with a PO128 code.
P0128 Coolant Temperature Below Thermostat Regulating Temperature.

Angelo

shorod
02-21-2019, 08:32 PM
If that's the only diagnostic code currently, there's a good chance your thermostat is stuck open and the engine is not getting to the expected operating temperature. Changing your thermostat may fix the issue. If you opt to change the thermostat, you may also want to make sure you can get a thermostat housing in the event you find yours damaged or damage it during the removal process.


-Rod

ford2688
02-22-2019, 05:43 AM
I did notice that the truck runs cold. The needle would reach just to
the low range on the gage. Could be stuck open.
Angelo

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