Will 2004 Jetta ECU work with 2005 Jetta

SAABNEWBIE · Jul 15, 2018

Double checking here now. Probably should have done that first. I ordered part number 038 906 016 H. I was not gonna break windshield wipers off until i got the replacement. VCDS showed the numbers but not the suffix letter. Can the gurus enlighten us?

drucifer · Jul 15, 2018

Are both mk4 jettas with BEW engines?
Is the one you're getting brand new or previously married to a car?
If used, was the immobilizer deleted?

I believe the letter at the end refers to a specific manufacturer that made the part for vw.
I'm sure others will correct if this is not the case.

SAABNEWBIE · Jul 15, 2018

drucifer said:
Are both mk4 jettas with BEW engines? Yes

"Is the one you're getting brand new or previously married to a car?" Was pulled out of a retired car

"If used, was the immobilizer deleted?" I don't know. Most likely not.

I believe the letter at the end refers to a specific manufacturer that made the part for vw.
I'm sure others will correct if this is not the case.

Waiting on the knowledge.

drucifer · Jul 15, 2018

http://forums.tdiclub.com/showthread.php?t=202957

oilhammer · Jul 16, 2018

ETKA shows H, Q, and AG suffixes for the BEW ECU, all are Bosch. No idea what the exact difference is, other than it is VIN split specific. Chances are, once the immo is deleted, they will all be interchangeable with each other.

The tuners probably could be of more help here.

jettawreck · Jul 16, 2018

Even if/when the immobilizer is deleted (unless you do other changes with keys/ignition/etc the engine won't stay running) unless you have the gauge cluster "paired" with the ECU the immobilizer light will continually flash, but the engine will still run. I've been ok with letting mine flash but will probably eventually have the cluster/ECU matched up.
Immobilizer delete is relatively inexpensive.

jetta 97 · Jul 16, 2018

jettawreck said:
Even if/when the immobilizer is deleted (unless you do other changes with keys/ignition/etc the engine won't stay running) unless you have the gauge cluster "paired" with the ECU the immobilizer light will continually flash, but the engine will still run. I've been ok with letting mine flash but will probably eventually have the cluster/ECU matched up.
Immobilizer delete is relatively inexpensive.

If you do Immo delete in ECU Immo light will flash only if you have unauthorized key that has not been program to immobilizer.
If you do only ECU swap with Immo delete all will be good.

jetta 97 · Jul 16, 2018

SAABNEWBIE said:
Double checking here now. Probably should have done that first. I ordered part number 038 906 016 H. I was not gonna break windshield wipers off until i got the replacement. VCDS showed the numbers but not the suffix letter. Can the gurus enlighten us?

If your car in MK4 then you should be OK.
BUT ,
Those cars had 2 different update over original software and this could be your problem. So those ECU are sold with original part number on top of the ECU label but when you scan with VCDS it could be different part number with different software version.
It was total of 3 SW versions and 3 Different part numbers.
Then problem will come at Glow plugs , Ceramic 7V vs metal 5V.

oilhammer · Jul 16, 2018

Yeah pretty much no matter what it will need a reflash.

SAABNEWBIE · Jul 16, 2018

Regarding reflash for 5v steel glow plugs, if I needed it, what is the least expensive and most reliable easy way to do this ?

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BobnOH · Jul 16, 2018

Bully any VW dealership to do it free. Otherwise you need a tuner. Should be under a hundred for a GP flash and an immobilizer delete, don't really know.
Is it possible to just leave the GP system alone?

SAABNEWBIE · Jul 16, 2018

I guess the adventure starts once i start pairing the new used ecu to my car. Keeping in mind that i only need to pass the smog test with it, i will do the least amount of work to get that done. If i can leave the glow plugs alone, i would.

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jettawreck · Jul 16, 2018

jetta said:
If you do Immo delete in ECU Immo light will flash only if you have unauthorized key that has not been program to immobilizer.
If you do only ECU swap with Immo delete all will be good.

Not to hijack the original thread, but are you saying if I get the key(s) programmed to the swapped in TDI ECU the flashing immobilizer light will stay off?
I swapped a 2003 TDI engine, ECU (had the immobilizer deleted) and cluster into a 2003 1.8 chassis and still using the gas chassis key(s). Runs great, immobilizer light flashes. Doesn't bother me much, but I don't drive it much at night.

jetta 97 · Jul 16, 2018

jettawreck said:
Not to hijack the original thread, but are you saying if I get the key(s) programmed to the swapped in TDI ECU the flashing immobilizer light will stay off?
I swapped a 2003 TDI engine, ECU (had the immobilizer deleted) and cluster into a 2003 1.8 chassis and still using the gas chassis key(s). Runs great, immobilizer light flashes. Doesn't bother me much, but I don't drive it much at night.

I said if you ONLY SWAP ECU.
If you swap cluster and do not have key programed to that cluster, then YES , immo light will flash,Or if you use unprogrammed key to existing cluster with Immo off in ECU car will start but immo light will flash .

OP ask only for ECU SWAP.

jetta 97 · Jul 16, 2018

SAABNEWBIE said:
I guess the adventure starts once i start pairing the new used ecu to my car. Keeping in mind that i only need to pass the smog test with it, i will do the least amount of work to get that done. If i can leave the glow plugs alone, i would.

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It all depend what you have in car , and what new ECU will come with.

-Original SW was 7V ceramic
-First SW Update was 5V metal
-Latest SW Update was 7v ceramic,

Example ,
you have original SW and get latest SW with 7V ceramic, then they are compatible.
But if you have SW with 5V metal and get ECU with 7V ceramic then they are not comparable it will burn your Glow Plugs.In this case you need to reflash ECU yo 5V metal. But Dealer can not do that . They can do only latest SW update with 7V ceramic.

How do you plan to Pair new ECU to your car?

oilhammer · Jul 17, 2018

SAABNEWBIE said:
I guess the adventure starts once i start pairing the new used ecu to my car. Keeping in mind that i only need to pass the smog test with it, i will do the least amount of work to get that done. If i can leave the glow plugs alone, i would.

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What exactly is the nature of wanting to replace the ECU in the first place?

SAABNEWBIE · Jul 17, 2018

I want to pass California smog test. Current ecu has tune with egr delete which causes egr readiness monitor to "fail or incomplete"

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oilhammer · Jul 17, 2018

OK, so you need a retune. Another ECU won't help you. And you'll have to jump through software hoops to get it to work, more than you likely would just having your existing ECU made to be OBD compliant.

And this assumes that your car has no EGR physical delete that the tester may notice and fail you anyway. Not sure how your testing there works.

BobnOH · Jul 17, 2018

Or keep looking and get a used ECU with the same part no. as what's in there. You might get lucky and find one near $150.
Also- And this assumes that your car has no EGR physical delete that the tester may notice and fail you anyway.

Will 2004 Jetta ECU work with 2005 Jetta

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