Faulty ECU - DTC P0601

[trctrctrc]

Hi all,

Putting this post up to track a fault and for future reference in the hopes it helps other people who may encounter the same problem. I have a 2014 VF SSV ute (L77 6.0) that has developed a sudden stall after approximately 40 minutes of driving or running, with the message "Engine Power Reduced" on the dash cluster. The car will not start afterwards, the dash goes through the usual process of starting without attempting to turn over the engine. The only way to get it to start after this is to clear the MIL (engine) light or disconnect the battery for >30 seconds and reconnect it - starting after this is OK and will subsequently reproduce the issue after 2-5 minutes of driving.

The ECU throws the error P0601 - Internal Control Module Memory Check Sum Error, from ECU 7E0. This malfunction is reproducible after about 40 minutes of run-time, consistently. I run a series of troubleshooting steps to rule out contributing factors to this issue, main step being battery replacement as it was on its way out - a bit of info online suggests similar codes are thrown when voltage inconsistencies are experienced by the ECU.

The behaviour of the issue goes as follows:

1. Dash cluster displays "Engine Power Reduced", check engine light is lit and instantly shuts off engine - this occurs after about 40 minutes of runtime
2. Transmission is thrown into neutral regardless of gear - car will simply coast to a halt
3. Fuel and temp gauges are held in typical running position but the tacho and speedo read 0
4. Upon attempting to restart the car, a relay click is heard, all interior electronics are turned off and won't turn back on until Start/Stop is pushed again - nothing happens with the engine
5. The engine will not restart unless MIL light is cleared by OBD utility or battery is disconnected for >30 seconds
6. Upon starting the car again it'll run like nothing happened and go back to 1. after about 2.5 minutes of subsequent run time

Next, and hopefully final step, is to replace the ECU. I'm waiting for a replacement ECU to arrive, once I get it I'll be getting a Holden dealer to flash it so the rest of the computers in the car play nice with it and then run some tests to hopefully not reproduce the issue.

The part number that suits my model (other models may vary) is: 12633238
Name: GM E38 or E38 Engine Control Module

Hopefully around this time next week I'll be getting the replacement ECU installed and flashed and the issue no longer occurs. Hopefully...

 

[Smashfist]

Definitely an ECU. P0601 is simply a module reporting it's failed an internal self-check. The troubleshooting guide for P0601 in any module is basically: check power and grounds. If all OK then replace the module.

They are repairable through the right place though (injectronics if I recall may repair them).

 

[Skylarking]

Yesterday I was typing up a reply with links but and thread disappeared before I hit the post button. So what I typed was lost

But it was similar to what @Smashfist said.

Though I did add that if you reprogrammed the old ECU with OS and calibration files, any faulty memory chip would see a faulty write verification phase that I’d assume the GM programing tools would/should perform (either during or post write). So if the issue is caused by a hard memory fault, you’d need the faulty chip replaced but if the issue is a soft memory fault (gamma ray, etc) because manufacturers are too cheap to use error correcting memory chips, such soft faults may be fixed by the write operations...

Whether the cost of Holden reprogramming your old ECU is worth the punt, I don’t know. Also don’t know how much it costs to find the faulty memory chip and replace it.

Being that I’ve also seen you can buy such ECU’s for $250 from the state, there are a few potions and their cost issues to consider.

 

[Smashfist]

because manufacturers are too cheap to use error correcting memory chips

Due to safety reasons, ECM's always use error correction and redundant memory. That's part of why they're typically quite expensive.

 

[Skylarking]

[

Due to safety reasons, ECM's always use error correction and redundant memory. That's part of why they're typically quite expensive.

I haven’t read any documents anywhere that states GM ECU utilise ECC memory so just assuming they are being cheap as usual.

Also, I haven’t pulled apart a modern ECU and checked the chips used so can’t confirm what memory is actually used. Old late ‘80s ECU definitely wasn't ECC memory.

As is, the only stuff I know where ECC is used is in servers and engineering workstations...

Not doubting you about the ECC memory on modern ECU but I wouldn’t agree that something is expensive simply because it costs lots to make... it’s usually expensive because it’s proprietary and it’s what people must pay (thanks to that proprietary lock-in)...

As for safety reasons/arguments, don’t nuclear power stations and US navy still use Windows XP in some/many instances

 

[trctrctrc]

ECU was replaced on Friday and all has been well since. I've got the old ECU on hand and when I get some time I'll look at opening it up and seeing if I can run some tests on the memory itself, if possible.