Code 42 EST

[Jax ZR1]

Just pulled the plenum and replaced injectors and starter put it back together and is still idling ruff and check engine light comes on, checked codes and got a code 42 electronic spark timing. It’s a 1990 ZR1 with just under 10,000 miles on it. Any ideas would be great thanks.

[XfireZ51]

Just pulled the plenum and replaced injectors and starter put it back together and is still idling ruff and check engine light comes on, checked codes and got a code 42 electronic spark timing. It’s a 1990 ZR1 with just under 10,000 miles on it. Any ideas would be great thanks.

Have u checked ur connector and the ignition module? Bent pin?

[Jax ZR1]

No I haven’t, is that under the plenum there are the two plugs under the plenum and two plugs at the back of that piece was hoping not to have to pull the plenum as I did not delete the throttle body cooling

[-=Jeff=-]

So as Dominic suggests.. there is that possibility of a bent pin, if so, it would be on the wide bolted connector and only if it was not inserted straight.

Here is the Code 42 info from FSM

[Jax ZR1]

Ok great thank you I will go have a look at that plug and get a multi meter right away

[Jax ZR1]

I took a photo of the pins after I got the plug off and it looks like a bent pin, will need to pull the plenum again to work on it. Anyone ever have luck reusing the plenum gaskets only been in a few days, don’t like doing that but don’t have access to new ones for a week or more. Thanks for the help and hopefully this works

[QB93Z]

I took a photo of the pins after I got the plug off and it looks like a bent pin, will need to pull the plenum again to work on it. Anyone ever have luck reusing the plenum gaskets only been in a few days, don’t like doing that but don’t have access to new ones for a week or more. Thanks for the help and hopefully this works

Yes, I routinely reuse Plenum gaskets if there are no visual defects.

Jim

[-=Jeff=-]

Yes, I routinely reuse Plenum gaskets if there are no visual defects.

Jim

Same

Also be VERY careful with straightening that pin on the Ignition Module

[Jax ZR1]

Thanks for the advice will try tonight I f I get time if not tomorrow, just so I know is the ignition module another part that is hard to find a replacement part for. Thanks again for the help very much appreciated

[-=Jeff=-]

Yes there are hard to find. Jerry is working on a replacement and I have a custom one in my car

[Jax ZR1]

Yes there are hard to find. Jerry is working on a replacement and I have a custom one in my car

Ok I will be as careful as I can thanks again everyone

[XfireZ51]

I took a photo of the pins after I got the plug off and it looks like a bent pin, will need to pull the plenum again to work on it. Anyone ever have luck reusing the plenum gaskets only been in a few days, don’t like doing that but don’t have access to new ones for a week or more. Thanks for the help and hopefully this works

Ur not the first one to have this happen. We all get excited to put the damn thing back together and get it running. Those pins are delicate. Care needs to be taken to ensure they’re inserted properly. If it don’t fit don’t force it.

[Jax ZR1]

Just finished doing it again and I’m still getting the same code, so tomorrow I’ll check it with multimeter and hope I can find the problem

[-=Jeff=-]

Yes run down the Diagnostic tree I posted (2nd page)

Let us know what you find

[Jax ZR1]

So this car has a gremlin in it, made an appointment at the closest chef dealership to Check the code 42. Got up this morning to make the hour drive and the car started fine idled great, better then it has since I bought it ran good could feel the secondary working, made the hour long drive no problems stopped to fill up with gas and then it wouldn’t start push started it and then the check engine light came on right away and the idle started going up and down again. Drove it to the shop and that’s where it sits, and I’ll wait and see what they say not a lot of hope right now. It the way I put a brand new starter in when I did the injectors.

[G8nightman]

O no not the dealer cant wait to hear what they come back with.

[lfalzarano]

Code 42 is the Selective Ride Control Switch - open contacts. It will set if the switch is not properly positioned in one of the three detent positions? It shouldn’t make the engine run rough? There must be another code that you haven’t read.


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[Jax ZR1]

My shop manual says a code 42 is electric spark timing . I’ll wait and see what the shop says, was really happy this morning when the car was running the best it has since I bought it and then just like that back to the same old crap again.

[-=Jeff=-]

Code 42 is the Selective Ride Control Switch - open contacts. It will set if the switch is not properly positioned in one of the three detent positions? It shouldn’t make the engine run rough? There must be another code that you haven’t read.


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My shop manual says a code 42 is electric spark timing . I’ll wait and see what the shop says, was really happy this morning when the car was running the best it has since I bought it and then just like that back to the same old crap again.

Both are correct.. if I am troubleshoot a Check Engine light.. 42 is EST

if I am checking the SRC system, 42 is SRC switch, open.

Jax, I assume you are jumping A and B on the ALDL, not A and C.

[-=Jeff=-]

Hey Jax,

did you check the MEMCAL in the ECM? Check to be sure it is fully seated. Also when you straightened the pin, was it still solid?

[Jax ZR1]

Yes the pin was solid and I checked that code with a code reader set on ecm codes not the abs setting so I believe it is est problem. Still waiting to hear back from the shop.

[XfireZ51]

Yes the pin was solid and I checked that code with a code reader set on ecm codes not the abs setting so I believe it is est problem. Still waiting to hear back from the shop.

From ur description, sounds liike something intermittent. I would start the car and jostle the harness connectors on the ICM and ECM.

[Jax ZR1]

From ur description, sounds liike something intermittent. I would start the car and jostle the harness connectors on the ICM and ECM.

Ok I will try that if they can’t find anything at the shop still waiting to hear from them, so I can go pick up the car.

[Jax ZR1]

So the shop thinks they have the code 42 fixed but can’t figure out why the starter quits working after the car gets hot, so going home with a no start when hot problem new starter didn’t fix that. May have to pull the plenum and look at the starter, going to delete the throttle body coolant line this time thanks for the help. Any ideas for the starter would be great but I’ll start another post when I start that

[Jax ZR1]

Sooo just kidding as soon as the shop gave me the keys back went to drive away and because the car was warm from moving out of the shop it wouldn’t start and had to push start it and the check engine light came back on right away drove it the hour home and I guess I’ll try again myself. Shot in the dark if the cam position sensor is cracked and allowing oil inside it could it cause these problems, cause I’m looking for one of those as well, have a lead on one so going to follow upon that, and the starter problem I seen on here someone talking about putting a resister in the start wiring would that help my problem

[-=Jeff=-]

Cam sensor does not directly affect ignition module. Open the cover on the ECM and check the MEMCAL if it is loose, it will cause the code 42

[Jax ZR1]

Cam sensor does not directly affect ignition module. Open the cover on the ECM and check the MEMCAL if it is loose, it will cause the code 42

Ok I’ll try that been a long day today so tomorrow’s job thank you

[Marc Haibeck]

Considering that the problem started after installing the ignition module connector, I think that it's most likely that there is a problem with the connector. Sometimes the female pin in the connector gets crushed to the side or pushed back. I would remove the D connector on the ECM and measure the resistance of the IC (pin D1) and Bypass lines (pin D12) on the ignition module. They should not be over 10k ohms to ground. If so, there is an open circuit.

A silent no start with a hot engine is likely caused by friction in the starter solenoid or low current to the solenoid.

[Jax ZR1]

Considering that the problem started after installing the ignition module connector, I think that it's most likely that there is a problem with the connector. Sometimes the female pin in the connector gets crushed to the side or pushed back. I would remove the D connector on the ECM and measure the resistance of the IC (pin D1) and Bypass lines (pin D12) on the ignition module. They should not be over 10k ohms to ground. If so, there is an open circuit.

A silent no start with a hot engine is likely caused by friction in the starter solenoid or low current to the solenoid.

After work tonight I will check that thanks Marc

[Jax ZR1]

So again last night I started the car went for a drive no codes but I checked the memcal card and it was tight, it is one from Marc. But again no start when it was hot, found that there is only 5.5 volts going to the starter solenoid and if you give 12 off the battery it will start, not sure why I have such low voltage. Thinking that the 5.5 volts works when starter is cold but not enough when the starter gets warm

[-=Jeff=-]

Ok so the code 42 is gone? The no start hot is like Marc mentioned starter related.. I did a relay mod as well as fix my starter solenoid to fix the no start issue with my car

[Jax ZR1]

The relay mod is that the one I have found on here tapping into the purple wire and the new relay that some think is right and some wrong. I think I will try it cause I would like to drive the car more but if it doesn’t start when warm hard to go anywhere other then for the odd drive . Thanks Jeff the code 42 was gone last night so it’s hard to check much when it working comes and goes so was working on the no start last night only

[Jax ZR1]

Drove the car yesterday after the relay mod and the no hot start problem seem to be gone as for the code 42 it never came on during the numerous test runs so here is hoping it was a loose MEMCAL, looking forward to spending some time driving it, thanks for the ideas and help. Hope everyone gets a chance to get out and drive their cars this weekend.

[lfalzarano]

Just came back from running errands at several stores. It’s just fun to drive. DNS is not a problem with a fresh battery.


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