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Forever cranking, never starting. No spark & ECM not communicating


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I have a 2006 Subaru Impreza WRX. 

 

A few weeks ago, it was running fine and then a few minutes later went into a limp-home mode and wouldn't rev over 2000 RPMs. When I connected up a code scan tool, it was initially providing the error code; P0607 - Control Module Performance. Then awhile later I connected it back up to the car, but the ECM was now unresponsive with scan tool.

 

So I brought it to my mechanic, 

 

- Found and put in another used ECM and still no start and no communication with scan tool.
 

- Re-checked all power and grounds for ECM still good, even followed wiring to their source at power or ground.
 

- ECM still not firing injectors or ignition coils.
 

- My mechanic then brought it Subaru, and they connected it up to their laptop, but still no communication.

 

Recommendation is to buy a new ECM and replace it, or to have another go at the engine harness and either repair or replace it.

 

What do you think?

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- Found and put in another used ECM and still no start and no communication with scan tool.

 

 

Can you swap 2005+ ECU's just plug and play or is there some more complicated process due to immobilizer, CANBUS, programming....?

 

I'd get the FSM and look through the diagnostic procedures for that code - FSM's are free and all over the internet. 

 

What is the history of the car - you bought it showroom new and have put every reliable mile without a glitch on it up until the point this happened? 

 

Or it was totaled, salvage, rebuilt, then sat through flood waters, rebuilt again, stolen, recovered, and repaired, then you bought it at auction cheap?  

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Can you swap 2005+ ECU's just plug and play or is there some more complicated process due to immobilizer, CANBUS, programming....?

 

I'd get the FSM and look through the diagnostic procedures for that code - FSM's are free and all over the internet. 

 

What is the history of the car - you bought it showroom new and have put every reliable mile without a glitch on it up until the point this happened? 

 

Or it was totaled, salvage, rebuilt, then sat through flood waters, rebuilt again, stolen, recovered, and repaired, then you bought it at auction cheap?  

 

- My understanding is that you can swap the ECM with another and the car will start and run. It would just need to be reprogrammed for the anti-theft/door locks.

- I did look up the code before it died. It's a generic code that basically means it could be anything electrical. As identified here; https://www.obd-codes.com/p0607

- I bought the car new and have had it ever since. Car worked great. Had a CEL for the past 4 years, had it looked at, was caused by a bad sensor, but Subaru assured me there was no concern.

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Sounds electrical to me, especially the ecu was telling you before it lost communication. Time to start hunting. Maybe it rubbed somewhere and cut through some wires or something came unplugged, hopefully. 

I hate when you take your car to the dealer and you are expecting them to know the cars inside and out and they don't. It's like taking them to a auto mechanic who has never worked on a Subaru. 

That is why I love this forum and work on all of my own stuff. You got these days. Too expensive otherwise. 

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I'm sure it's been tried, but, a battery neg terminal dosconnect might be helpful. my 06 WRX wagon has gone into limp mode twice. Once it 'seemed' due to a weak battery, the other time the problem was cured with a battery disconnect reset.

 

but your issue seems more severe...?

 

I THINK some cars have had a wire harness become abdraded by the steering column's u-joint - as said above, worth looking around for broken grounds and other wiring problems.

Edited by 1 Lucky Texan
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I'm sure it's been tried, but, a battery neg terminal dosconnect might be helpful. my 06 WRX wagon has gone into limp mode twice. Once it 'seemed' due to a weak battery, the other time the problem was cured with a battery disconnect reset.

 

but your issue seems more severe...?

 

I THINK some cars have had a wire harness become abdraded by the steering column's u-joint - as said above, worth looking around for broken grounds and other wiring problems.

 

- Battery is good. I have tested the voltage, and tried a different battery.

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You can't just swap and plug and play 05+ stuff.  I would really dig into this topic before you assume that's all good.  The ECU, keys, and immoblizer box are married together, they must stay as a set...maybe more or less components.... it's the reason everyone swaps 04 and earlier stuff and says dont' even try 05+ unless you're going stand alone. 

 

i think you need to dig into and verify that topic - google "2005 Subaru immobilizer swap" or some variants of that phrase and I think you'll find what I'm referring to. 

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Agreed - the immobilizer is just that - it IMMOBILIZES the car. You must marry the ECU to the VIN and the key. It is possible to do this without the Subaru dealer tools but it's not a simple or guaranteed process. Our tuner does it and never speaks of his ability to do as a 100% sure bet. 

 

The dealer will probably not marry a used ECU. But a good tuner can probably do it. There may also be custom ROM's out there that can disable the system..... I've heard some talk about that and I know it's been done on the Mitsubishi EVO (I've done it personally on those).

 

GD

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I had assumed since it was already at the dealer that they already tried that. Maybe not. Why won't they program a used ecu? Or they just can't?

 

Maybe they can, but they probably won't. Has to do with their warranty policies - all the Subaru dealers I know of put 3 year/36,000 on all repairs. Can't warranty a used part. They would only consider it if there was no other option (IE the part is no longer available through SOA). 

 

GD

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I had assumed since it was already at the dealer that they already tried that. Maybe not. Why won't they program a used ecu? Or they just can't?

Yes, it was already at the dealer, but they couldn't establish communication to either of the ECUs, similar to the scan tool. They have no issue with reprogramming a used ECM, they just need the VIN number of the car it came off of...and of course they will charge for the reprogramming, and there is no warranty on it. Both ECUs the original from my car and the used ones show similar symptoms...but of course we've never seen the used one working, so we don't know if does. It's also possible that the car fried the used ECU the same as the original, however probable that is.

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Used/unregistered ECM should communicate with the scan tool, even if the car won't start.

 

Load test power& ground circuits to ECM-  They can show voltage/continuity but not be able to carry current, due to corrosion or broken strands of wire.

 

Check for loose or pushed out terminals in ECM connectors.

 

Look for mice.  I can't count the number of electrical issues I've run across caused by mice eating things...

 

Unplug ETC, APP, cruise control, brake switch, ABS unit and see if ECM will communicate.  May be a short pulling down a reference voltage circuit.  If it talks, then start plugging things back in one at a time until you lose communication again.  The last thing you plugged in may then be the source of your problem.

 

Other than that, I got nuthin'  :D

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We've had issues with certain VW's not communicating during inspections. Similarly, the voltage is too low. Disconnecting the ABS computer during the inspection allows it to read. I agree with silent bob that his could potentially be the issue.

In those cases, there was still enough voltage for the scanner to read, but not for the NYS computer. Go figure

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So new development...it's fixed...there was a lot of corrosion in the air pump solenoid / pressure sensor and it shorted out...crazy how a sensor can completely disable a ECU and make the car completely undriveable. Anyways, unplugged it, and the bloody thing started working.

 

Thanks gents for all your help!

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