Help! Module 1 C41 Module 4 Err Module 9 H72

[1992BearC4]

Ya fuel pump kicks on for a few and the fans do come on also. Something also turns on in the center firewall area for a few seconds also. Every couple times when the key is in the run position after about 10 seconds everything starts clicking on and off and then goes back to normal, on a side note the key chime only works for the first key insertion then never works again until you disconnect the battery.

I will try that and let you know.

 

[ecss]

The key chime is controlled by the CCM so not a problem at this time.

If you turn the ignition On and you have the C68 climate control system when you press the Eng/Met button does
the temp display in the C68 control head change from degrees Cent to degress F and vise versa?
That tells you the serial bus is working.

 

[1992BearC4]

1. Disconnected the Gray ECM connector and no ses light.
2. Key On ENG/MET changes both the temp display and the LCD Dash display from English to Metric.
3. Took out MEM/CAL same symptoms fans on and SES light wont flash codes only stays lit.

 

[ecss]

Good 1. Disconnected the Gray ECM connector and no ses light.
Good 2. Key On ENG/MET changes both the temp display and the LCD Dash display from English to Metric.
Bad 3. Took out MEM/CAL same symptoms fans on and SES light wont flash codes only stays lit.

So if the memcal is installed or not when you turn the ignition On, the fans come on and the SES light is always on?

Will the engine crank and try to start even with the memcal out or does it crank and try to start only with the memcal installed?

 

[1992BearC4]

When speaking of the memcal are you talking about the small rectangular chip that is part of the assembly that plugs into the circuit board of the ECM or do you want the whole assembly unplugged from the ecm ?

 

[ecss]

When speaking of the memcal are you talking about the small rectangular chip that is part of the assembly that plugs into the circuit board of the ECM or do you want the whole assembly unplugged from the ecm ?

The memory chip is soldered in place so I mean the whole assembly that ejects from the mother board.

 

[1992BearC4]

With the whole assembly out the fans still come on and the SES light is on solid and it will turn over but no start.

 

[ecss]

With the whole assembly out the fans still come on and the SES light is on solid and it will turn over but no start.

With the memcal assembly out did the fuel pump prime for 2 seconds?

 

[1992BearC4]

Yes it did

 

[ecss]

Yes it did

Interesting.

Since both ECM's are behaving the same way, the problem points to the cal pak.


Best way to test it is to swap it with another one. ad

Supposedly that assembly contains circuitry to allow the car to run with partial ECM circuit failure.

The Eprom can be checked by reading it and verifying the checksum matches with the data read but
I know of no way to check the limp home mode circuitry that is on that small circuit board.

There is a guy in Utah with a 92 who I believe could test your ECM and cal pak for you.

If you want, Private message me your e-mail and I'll give him the information on how to contact you and if
he thinks he can help you he can contact you.

 

[1992BearC4]

How is the reprogramming done ? for the EPROM

I'm looking on EBAY and cant find that listing ?

 

[ecss]

How is the reprogramming done ? for the EPROM

I'm looking on EBAY and cant find that listing ?

Read my last post again. I modified it. I think what I'm recommending is your best bet and
the best way to isolate your problem.

 

[1992BearC4]

Here is something interesting I plugged in the other ECM with out the whole EPM module not installed into the board and it started and ran kinda stumbled but the first time its ran in almost 18 months don't know what to make of this ?

 

[ecss]

Here is something interesting I plugged in the other ECM with out the whole EPM module not installed into the board and it started and ran kinda stumbled but the first time its ran in almost 18 months don't know what to make of this ?

If you short pin A to pin G do you still get DTC 41?

 

[1992BearC4]

If you short pin A to pin G do you still get DTC 41?

Do you want the whole eprom assembly out of the ecm or installed ?

 

[ecss]

Do you want the whole eprom assembly out of the ecm or installed ?

You said in your last post the car ran.
With that configuration when you short pin a to pin g and look at the LCD does DTC 41 still set?

 

[1992BearC4]

I will try it with and without the eprom assembly and let you know the results codes start no start etc thanks so much for all the help !

 

[1992BearC4]

OKAY with the EPROM installed it starts and runs but stumbles and security and sys flashing and service ASR is on when jumpered pins A & G together I get C12 C41 H41.

Same result with the EPROM out of the ECM. except for the C12.

When it does stumble it sounds like the relays are clicking on and off inside and outside the car ?

The ENG/MET function still works both ways.

 

[ecss]

OKAY with the EPROM installed it starts and runs but stumbles and security and sys flashing and service ASR is on when jumpered pins A & G together I get C12 C41 H41.

Same result with the EPROM out of the ECM. except for the C12.

When it does stumble it sounds like the relays are clicking on and off inside and outside the car ?

The ENG/MET function still works both ways.

Makes no sense about the relays clicking.
I think what I recommend in post 50 is your best bet.

What are the letters on the Eprom label?
BAFL
BAFM
AZUR
AZUP
BAFN
BDBJ
BDBK

A cal pak for sale
93 Corvette 350 LT1 Auto Prom Memcal Chip 1993 BDBL 4782 C4 Vette | eBay

 

[1992BearC4]

makes no sense about the relays clicking.
I think what i recommend in post 50 is your best bet.

what are the letters on the eprom label?
Bafl
bafm
azur
azup
bafn
bdbj
bdbk

a cal pak for sale
93 corvette 350 lt1 auto prom memcal chip 1993 bdbl 4782 c4 vette | ebay

bdjs