Code 42???

[turbov6joe]

I drove my TR into town the other day and ran some errands. When I went to restart the motor it cranked fast for a few revs, slowed down like it was under load and sped back up but didn't start.

I cycled the key and it did the same thing again.

I cycled the key again and it fired up throwing a SES light (code 42).

It was running kinda rough but no other problems. I turned the key off, restarted the motor and it fired right up...easier then normal. I noticed that the SES went out and the motor was purring like normal.

I noticed that this only happens when the motor has been running for a while and is hot...it's never does it when the motor is cold??? I've never run into this before...sound like a familiar problem to anyone? What was the cause?


TIA

 

[Silver 'T' Top]

Mine did that once last summer. The computer seemed to be toastier then normal at the time, let it sit for about 30 minutes and it was fine. Would still heat up, so we swapped it out with another.

 

[BW Jones]

code 42

when your engine is cranking, the ignition module sends a reference signal to the ECM. if the engine speed is below 400 rpm, the ign module controls the timing. when the engine speed exceeds 400 rpm, the ECM sends a 5V signal on the bypass circuit allowing the ECM to then control the timing through the EST circuit. if you have an open or ground in the EST circuit, the engine will stall and set a code 42.

sounds as though you could have an intermittent connection. check the B4 & D5 terminals of the ECM harness for good connections. i'd also make sure the ign module connector does not have bent pins and is mated properly to the ign module.

bw jones

 

[BW Jones]

if all the connections/connectors are o.k., either the ECM or the ignition module is bad. i'd suspect a problem with the ignition module because they are subject to plenty of heat and i've seen them look like a puddle of tapioca pudding upon inspecting with the coil pak removed.

bw jones

 

[turbov6joe]

if all the connections/connectors are o.k., either the ECM or the ignition module is bad. i'd suspect a problem with the ignition module because they are subject to plenty of heat and i've seen them look like a puddle of tapioca pudding upon inspecting with the coil pak removed.

bw jones

Thanks for the advice, I'll check both. Now that I'm thinking about it, the ECM seems like it's running hot and for a while there I was going through coil packs one right after the next...maybe both are shot? I'll replace on at a time and see what happens. Anyone know the the IM's are still available new?

 

[turbov6joe]

Mine did that once last summer. The computer seemed to be toastier then normal at the time, let it sit for about 30 minutes and it was fine. Would still heat up, so we swapped it out with another.

Any problems since???

 

[85HOT-T]

Typical causes for this code include:

1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM

 

[1quickfrc]

did you ever solve your code 42?

i just had one pop up and was wondering if you fixed it/ what the problem was

 

[Silver 'T' Top]

Any problems since???

Just came back across this, no problems after swapping computers.... up till the time car was stolen earlier this year. :frown:

 

[at7we2]

another code 42...

good information in the posts above. My GN just threw a code 42 today. It's done this a few times before in the last 3 years. In that same time frame, I've been dealing with an intermittant popping/stumbling under boost. I also had a problem with it dying and not restarting for a while although it has not done that in nearly a year. The popping and stumbling is intermittant so it's been VERY hard to diagnose. The engine will also occassionally misfire with the AC on. If I turn the AC on or off or change the blower fan speed, it will frequently make the engine stumble and the tach. needle jump. Today I had the AC on and the engine started running a little rough - I looked at the tach (Autometer) and it was twitching irratically about 100-200 rpm. As soon as I turned the AC off, the engine smoothed out and the misfire dissappeared. I have no idea if this is related to the code 42. It didn't set that code until about 5 miles down the road. I don't know if all these symptoms are related or if they are caused by different problems. Can a problem with the EST wire cause all of this?

 

[at7we2]

Typical causes for this code include:

1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM

if I'm not mistaken, the EST wire is the white wire from the coil module to the ECM, right? It's also the wire you have to splice into to install a Translator Plus so the T+ can control the spark timing, right? What about the "BYPASS" wire, where is it, what color is it?

Thanks,
Rob

 

[gsgns4me]

if I'm not mistaken, the EST wire is the white wire from the coil module to the ECM, right? It's also the wire you have to splice into to install a Translator Plus so the T+ can control the spark timing, right? What about the "BYPASS" wire, where is it, what color is it?

Thanks,
Rob

Tan and black. Some one else on the board gets credit for the link, I just had it saved.

 

[buickin87]

Please check first of all if the EST wiring is ok. Do you use Maftpro or Translator? If, check at first the wire tapping. I had breakage problem near the ECM, where I had made the solder joint for Maftpro wiring and not supported that soldering point properly into ECM wiring bundle. It broke, when I removed ECM for the chip change.

 

[at7we2]

excellent link!

gsgns4me - EXCELLENT link!!! Thank you! :biggrin:

I dug out my turbo Regal wiring diagram book last night and discovered the ESC (not EST) wire was the tan and black wire, but there is no trouble shooting proceedure in my book. I'll run through that process tonight.

buickin87 - I'll be sure to check the wiring. I've been working on this problem for 3 years now. about two years ago I discovered the EST (white) wire was damaged out at the coil module. I cut out the damaged section and soldered the wires back together. I thought that took care of the problem but it didn't. I'll run through the diagnostic procedure in the link above and also be sure to trace the EST (white) wire as far as I can from the coil module and from the ECM.

and for anyone reading this who might be confused, there are two wires that come into play here, the ESC (tan and black) "Electronic Spark Control" and the EST (white) "Electronic Spark Timing" wire.

Thanks guys. I hope this information helps the original poster also.

Rob