1988 F250 code15
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1988 F250 code15
I have this 1988 F250 with the 460 and the gas milage is baad!! (about 6-7 mpg) so I pulled the codes and and a code 15 comes up as an active code and a code 41 comes up as a memory code . replaced the EEC and the O2 sensor, everything apears O.K. for a couple of days then BINK the CHECK ENGINE light reappears again, so I pulled the codes again it's 15 and 41, what is the real meaning of code15?
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From: Baltimore
Code 15 is Power interruption to Keep Alive Memory.
Pin 1 of the EEC should be at least 10.5 volts because
the voltage comes from the battery.
The actual wire to Pin 1 comes from a lug on the Starter
Solenoid. This wire also has a fusible link built in to it.
I would recommend you clean that cable connection at
the Starter Solenoid and also measure the Voltage at Pin 1 of the EEC.
What may be happening is you're loosing the voltage or the voltage is dropping below 10.5 volts at Pin 1. This causes the loss of the data stored in some of the Computers memory.
I believe the Computer stores data in this memory when the computer is in the learn mode. Anytime power to the Computer is disconnected and reconnected, when you drive the vehicle it goes through a learn mode and the Computer stores this data/information in this memory.
My guess is Code 15 is the problem and 41 is a by product because of Code 15.
41 is Oxygen sensor lean for over 15 seconds which you should never see if the Computer is in Closed Loop.
(Fuel mixture controlled by the Computer using the Oxygen Sensor).
When the Computer is in Open Loop, it doesn't use the information from the Oxygen sensor for fuel mixture which may explain your poor gas mileage.
Pin 1 of the EEC should be at least 10.5 volts because
the voltage comes from the battery.
The actual wire to Pin 1 comes from a lug on the Starter
Solenoid. This wire also has a fusible link built in to it.
I would recommend you clean that cable connection at
the Starter Solenoid and also measure the Voltage at Pin 1 of the EEC.
What may be happening is you're loosing the voltage or the voltage is dropping below 10.5 volts at Pin 1. This causes the loss of the data stored in some of the Computers memory.
I believe the Computer stores data in this memory when the computer is in the learn mode. Anytime power to the Computer is disconnected and reconnected, when you drive the vehicle it goes through a learn mode and the Computer stores this data/information in this memory.
My guess is Code 15 is the problem and 41 is a by product because of Code 15.
41 is Oxygen sensor lean for over 15 seconds which you should never see if the Computer is in Closed Loop.
(Fuel mixture controlled by the Computer using the Oxygen Sensor).
When the Computer is in Open Loop, it doesn't use the information from the Oxygen sensor for fuel mixture which may explain your poor gas mileage.
Last edited by F150xlt; Oct 11, 2004 at 03:03 PM.
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From: Baltimore
If you have a Digital Volt meter, disconnect the electrical harness/plug going to the Computer and measure pin 1 to ground.
You should measure 10.5 volts or higher.
The voltage should always be there because it comes from the battery.
I'm not sure if the connector pin numbers are marked on the cable plug.
You should measure 10.5 volts or higher.
The voltage should always be there because it comes from the battery.
I'm not sure if the connector pin numbers are marked on the cable plug.
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I did that and it showed battery voltage , I cleaned all conections , drove it about 20 miles every thing apears fine on the freeway , it dosen't care for in city stop and go . my next step is to put a volt meter inline with the wire going to pin 1 and monitor while driveing to see if it looses voltage when things get hot under the hood.
