Need Help-New E92 ECM

First off I'll say I'm very new to HPT, I've done an online course and watched a ton of Goat Rope Garage videos among others, just dangerous now. I have been calling around trying to find someone locally that could help me but no luck. Also I've been searching for about 5 days now so I figure I either don't know what I'm looking for or it can't be done.

I swapped a 2017 Gen 5 L83/6L80 into a Defender, harness and programming done by Speartech using the FPCM and PWM fuel pump. It's thrown 4 or 5 codes all relating to the fuel sensor circuit (P018B,C,D and P023F). It starts great, runs for a couple seconds, then dies (verified VATS and Starter Diag off). I went through the GM circuit test procedure a few times all with the same conclusion that the ECM needs replaced because it's not reading the sensor return voltage 0.00V.

I'm using VCM scanner to read

Fuel Pressure Requested-60psi+-
Fuel Pressure SAE-58psi
Fuel Pressure Sensor still at 0.00V
Fuel Rail Pressure-around 2000psi

First question, are these reliable readings to use for troubleshooting?

So after following the GM procedure it says my ECM needs replacing so I ordered a new one from the local dealer thinking $250 is worth it if I can get past this. I figured I'd have to copy over my tune and that's it. Now I'm reading I need to get the dealer to flash the operating system and VIN on it first, is this true?
I talked to a local tuner and he said I can do all that with HPTuners in the car so now I don't know what to do. If I could get some guidance I'd like to do it myself as a learning experience if nothing else. Can I do this with a new ECM using HPT?

I really appreciate the help, I enjoy learning this but it's hard to do on my own,
Sean

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Originally Posted by sgo70

First off I'll say I'm very new to HPT, I've done an online course and watched a ton of Goat Rope Garage videos among others, just dangerous now. I have been calling around trying to find someone locally that could help me but no luck. Also I've been searching for about 5 days now so I figure I either don't know what I'm looking for or it can't be done.

I swapped a 2017 Gen 5 L83/6L80 into a Defender, harness and programming done by Speartech using the FPCM and PWM fuel pump. It's thrown 4 or 5 codes all relating to the fuel sensor circuit (P018B,C,D and P023F). It starts great, runs for a couple seconds, then dies (verified VATS and Starter Diag off). I went through the GM circuit test procedure a few times all with the same conclusion that the ECM needs replaced because it's not reading the sensor return voltage 0.00V.

I'm using VCM scanner to read

Fuel Pressure Requested-60psi+-
Fuel Pressure SAE-58psi
Fuel Pressure Sensor still at 0.00V
Fuel Rail Pressure-around 2000psi

First question, are these reliable readings to use for troubleshooting?

So after following the GM procedure it says my ECM needs replacing so I ordered a new one from the local dealer thinking $250 is worth it if I can get past this. I figured I'd have to copy over my tune and that's it. Now I'm reading I need to get the dealer to flash the operating system and VIN on it first, is this true?
I talked to a local tuner and he said I can do all that with HPTuners in the car so now I don't know what to do. If I could get some guidance I'd like to do it myself as a learning experience if nothing else. Can I do this with a new ECM using HPT?

I really appreciate the help, I enjoy learning this but it's hard to do on my own,
Sean

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You do need to flash the ECM with the factory software and tune. Then you can load the tune you're running. I've done this a few times for people.

Quote:

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So after following the GM procedure it says my ECM needs replacing so I ordered a new one from the local dealer thinking $250 is worth it if I can get past this. I figured I'd have to copy over my tune and that's it. Now I'm reading I need to get the dealer to flash the operating system and VIN on it first, is this true?
I talked to a local tuner and he said I can do all that with HPTuners in the car so now I don't know what to do. If I could get some guidance I'd like to do it myself as a learning experience if nothing else. Can I do this with a new ECM using HPT?

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Brand new ECMs come with a "placeholder" flash in them. This is because the same ECM can be used on numerous vehicles. The GM OE programming process replaces the placeholder flash with the correct one for your vehicle based on the VIN provided to their tool. This process also writes the VIN into the ECM.

However, you should be able to just flash your current tune into the ECM (use Write Entire), though you will have to license the new ECM. Also, because there's no VIN in it, you may have to tell VCM Editor which ECM type it is.

Once you get it running you will need to perform a CASE learn, or else you will have a persistent P0315 code.

Okay, thanks a lot for the replies. I'm starting to think I should suck it up and let Speartech do it for me.

Sean

just browsing the thread, and its from January and the thread wasn't updated... was the harness from the same engine, re worekd, or did you buy the hanress somewhere else? There is a different high pressure rail sensor on the L83s around 2017... the sensors and wiring to ECU are different