Code 42 just popped

[billschroeder5842]

I just got a SES warning and my diagnosis said Code H42 or "EST System Malfunction". I went in and cleared all codes, but have not tried to re start yet.

This happened after an exceptionally long start/spin after I washed the car. Normally, the car will pop instantly or within a 1.5 seconds. This was about 5ish seconds.

I read up on Code 42 and found a lot of "it could be this, or it could be that' in relation to open circuits, wiring harness...etc.

Where is the most common place I should look?

The 91 is bone stock except for a Haibeck chip.

Thanks!

[XfireZ51]

I just got a SES warning and my diagnosis said Code H42 or "EST System Malfunction". I went in and cleared all codes, but have not tried to re start yet.

This happened after an exceptionally long start/spin after I washed the car. Normally, the car will pop instantly or within a 1.5 seconds. This was about 5ish seconds.

I read up on Code 42 and found a lot of "it could be this, or it could be that' in relation to open circuits, wiring harness...etc.

Where is the most common place I should look?

The 91 is bone stock except for a Haibeck chip.

Thanks!

An H code is from the CCM not the ECM. Does it flash on the DIC or on the digital display?

[billschroeder5842]

Sorry, no flashing just steady after start.

You are correct I did the CCM check.

Should I do the ECM just to check and cross reference?

[XfireZ51]

Sorry, no flashing just steady after start.

You are correct I did the CCM check.

Should I do the ECM just to check and cross reference?

They're discreet MALF Codes. So there wouldn't really be anything corresponding unless indicated.

[billschroeder5842]

OK.... FML....

I re read codes from both CCM and ECM and came up clear.

I went to start and the engine spun S L O W L Y and did not catch. I backed off the key and retried and nothing... no spining.

The rest of the electrical seems to work but I can tell the draw. I currently have the battery on a charger and might just get a new one.

Anything else I need to try?

[billschroeder5842]

**SOLVED**

I took the battery down to AutoZone and they put it on the meter. My home gauge showed 12.2 and theirs showed 12.3.... still low. The manufacture code said August of 2009. Yikes!

I bought a new one and put it in. Presto! Started right up and no fault codes. So I learned that a low battery will through a SES code? Huh?

Sometimes you get lucky with a ZR1 and get an easy fix!

[Racinfan83]

Yeah I learned my battery lesson couple years ago. Had a no start which was solved by some club members pushing me so I could pop start it which it did immediately. Drove it home and voltmeter check of batt was 11.9. So I got a new Interstate battery and now keep it on a tender since the car sits so much. I also did the "purple wire relay" mod just in case and have had no problem since.

[billschroeder5842]

I also did the "purple wire relay" mod just in case and have had no problem since.

Ok, you had me at "purple..."

So what is the "Purple Wire Relay" modification?

Thanks!

[Racinfan83]

https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-3.html#post1581564089

[billschroeder5842]

Thanks for the article!

[ssrszz4]

Before I started doing the battery disconnect thing I was buying batteries all the time since I have so many cars, now it's on a rare occasion.

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