4L80E Swap P0748
Thread Starter
Joined: Oct 2011
Posts: 175
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From: Eastern PA --> Southwest VA
4L80E Swap P0748 Just finished up installing a freshly build 80e in an 02' fbody. It has a CK D123 brake and will be running fixed line. All wiring changes and a segment swap have been done and I am assuming the P0748 is being thrown just due to the lack of EPC solenoid in the valvebody. The EPC control wire from the PCM (red with a black tracer) was removed from the pcm and the same wire from the trans is wired into my reverse and transbrake switches. My understanding is that this is a soft code being thrown because of the disconnect to the EPC solenoid, can I simply disable the MIL in hptuners and forget about it?
TECH Junkie
Joined: May 2012
Posts: 3,050
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From: Poplarville, MS
I don't know very much about 4L80Es or swaps but from what you said was done to the trans I would think you would be fine to simply just disable the code.
Last edited by bbond105; Jun 28, 2022 at 10:00 AM.
Moderator
Joined: Aug 2010
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From: Ann Arbor, MI
In case disabling the code is inconvenient (e.g. you don't a tuner), you can trick the ECU by connecting the EPC wire to a 15 Ohm, 10 Watt resister with its other end grounded. Tied up properly this could sit inside the trans pan.
TECH Junkie
Joined: Dec 2012
Posts: 3,615
Likes: 1,327
From: Iowa
if it's the EPC throwing the code...you do not want to hook it to ground.
The epc is a closed loop that controls amperage. It measures actual current flow.
so you can try a resistor just between the two EPC wires, but I've never tried this. Attempt at your own risk
The epc is a closed loop that controls amperage. It measures actual current flow.
so you can try a resistor just between the two EPC wires, but I've never tried this. Attempt at your own risk
