Will not fully seated Memory Clibration module always...

[Schrade]

... light up more than 1 DTC code?

I got a 42 4 module H. I cleared it, started diags running for a couple minutes, and it didn't light up again (I hate problems that go away by themselves).

FSM says first 'Intermittent' is to check MEM-Cal module for seating.

If it's not seated, won't it cause ALWAYS at least SEVERAL DTC's, instead of just one??

[XfireZ51]

If you put it into DIAG mode, it should just give you 1 + 2 flashes, 3 times, then repeat. Have you looked at the prom? The blue and white levers on each end should be locked in. Is your MALF code for the ECM or CCM?

[Schrade]

Haven't started digging yet there Darryl; waiting to see if the code lights up again here...

Diagnostic mode LCD showed proper when reading, and when cleared.

Loose ground somewhere probably - haven't checked any system ground connections either. LCD flickers occasionally too.

Still trying to de-compile the automatic install, and get it zipped up.

[XfireZ51]

Sounds like a CCM issue

[Schrade]

Originally Posted by XfireZ51

Sounds like a CCM issue

Funny that you say that there Sir; also saw when I bought it last year, a module 1 CCM H72, which I believe is voltage deviation...........

32k car shouldn't have grounds problem otherwise.

Corrosion in some grounds I'm sure; previous owner had the headlight motor short, which was draining the battery. He also had mounted an onboard trickle charger for this. Fumes HAD to be involved.

[XfireZ51]

Those are CCM codes, not ECM.

[Schrade]

Originally Posted by XfireZ51

Those are CCM codes, not ECM.

The module 4 H42 is ECM I think...

[XfireZ51]

Originally Posted by Schrade

The module 4 H42 is ECM I think...

You don't read ECM codes on the speedo display. You read them by counting the flashes of the SES light on the DIC.

[Schrade]

Originally Posted by XfireZ51

You don't read ECM codes on the speedo display. You read them by counting the flashes of the SES light on the DIC.

That's how my '87 was, but this one ('90) isn't flashing???


ed.:
OK - I'm thoroughly confused now.

So I plugged in the clip again. Am I puttin' tunnel vision on the LCD, and missing the SES flash? Nope.

I'm lost.


2nd ed.:
My '90 FSM says module 4 is for ECM.
And it's displaying in the LCD???

[Schrade]

Originally Posted by Schrade

That's how my '87 was, but this one ('90) isn't flashing???


ed.:
OK - I'm thoroughly confused now.

So I plugged in the clip again. Am I puttin' tunnel vision on the LCD, and missing the SES flash? Nope.

I'm lost.


2nd ed.:
My '90 FSM says module 4 is for ECM.
And it's displaying in the LCD???

bumpin' this one here...

Am I missing something here with Z package?

Is diagnostic readout different from base model L98 / LT1?