1999 C70 quit running while driving down the road ( recloned ECU) Topic is solved

[scot850]

If you need the ETM re-built you can now order the re-build through FCPEuro. You get the instructions from them but ship the ETM directly to Xemodex. Worth checking if that repair still has the lifetime warranty on it?

Price is not too ridiculous.

Neil.

[volvooh]

Thanks, Neil. The repair was done as part of the volvo recall at a dealership. It is no longer under warranty.

When the ECM came back online after sitting all night I got 3 codes:
ECM 720 A- Communication with immobilizer
ECM E000- Communication Error
ECM-912A COMMUNICATION CONTROL MODULE OR INTERNAL FAULT IN CONTROL MODULE
STATUS CHECK

Apparently my ECM has a hard time communicating! Interestingly it won't start this morning either.

I'm thinking this points at the ECM as the culprit?

[abscate]

A reseat might be worth it, too.

Negative battery terminal off, then pull ECU out. You are supposed to use a tool for this but I think there is a thread with pictures on how to release the clamps with two screwdrivers back and forth.

Inspect pins for corrosion, then put it back in.


ECM 720A info

ECM-720A IMMOBILIZER COMMUNICATION
DIAGNOSTIC TROUBLE CODE (DTC) INFORMATION

Condition
This diagnostic trouble code (DTC) indicates that the configuration between the engine control module (ECM) and the immobilizer does not correspond.
The immobilizer transmits the VIN code to the engine control module (ECM) at start attempt. Diagnostic trouble code (DTC) ECM-720A is stored in the engine control module (ECM) if the engine control module (ECM) interprets the code as faulty or missing. The engine control module (ECM) will not allow the engine to be started.

Condition
none

Possible source

Faulty signal:
an engine control module (ECM) that does not correspond to the immobilizer code has been installed
an immobilizer that does not correspond to the engine control module (ECM) code has been installed
defective immobilizer
defective engine control module (ECM)
open-circuit in the communication between the immobilizer and engine control module (ECM).
Condition
engine does not start

[volvooh]

Anything is worth a try, right?

As stated in my last post I had the immobilizer code and car would crank and not start. I have been dealing with this issue off and on the past two summers and was always remedied by locking and unlocking, as I did this morning. The car then started today after I did that. In addition to my other woes, I do think I have a suspect antenna ring.

At any rate, I am doing another test today. I am leaving the car unstarted in the run position- with a battery charger on the battery- to see if the ECM cuts out like it did yesterday when the car stalled several times. My theory is that the ECM is getting too warm and shutting down. I'll let you know the results.

[abscate]

Volvooh..recent resurfaced thread here on cloning ECU to solve no start

viewtopic.php?f=9&t=50291&p=250152#p250152

[volvooh]

Thank you abscate. You have been a tremendous help. I replicated my result twice: Once the key is moved to the "run" position, the ECU will only operate for about 15 minutes. After which, my scanner can no longer communicate with the ECU and the car will not start.

I pulled the ECU this morning (really not the difficult even without the "tool") and will be in contact with ARD. I talked to them earlier in the week and the charge to clone is $125 (plus of course providing a donar ECU). I hope this solves the issue and my discussion thread can get the trendy green checkmark after it!

[volvooh]

I wanted to post back with an update. I received both my original and cloned/doner ECU back from ARD yesterday and installed in the afternoon. I have had no stalls with the new ECU after driving about 25 mi or so. With the old unit the car would only run for about 15 mins before shutting down.

I am causiosly optimistic that the cloned ECU will solve the issue. In speaking with ARD, he examined the original ECU and found evidence of the chip overheating.

Crossing my fingers...I'll post back later in the week with another update.

[abscate]

Tentative...

IMG_2029.jpg (59.79 KiB) Viewed 1784 times

[wizechatmgr]

I may be tempted to crack mine open and either apply an additional heatsink or add heatsink compound and a bridge to the case.

Did they happen to have a picture of the location in question?

[volvooh]

No, unfortunately he was short on the details. I have not opened it myself, I do think with electronics there is also a telltale "fish" order that indicates an overheat- but that's just a guess there. He did say as many others on MVS this is an exception v. rule these ECU fail. Should have played the lottery last week. Just my luck.

I am not an electronics/hardware guy, but I’d say the overheat issue was likely to be more with a short that developed in the board or chip. He did not see anything visually, but I think to do a complete post-mortem requires a meticulous review of the each circuit and more patience than most of us, myself included, have.