Check Engine Light

[KEENO]

Hello All...



My Check Engine Light came on today when I went to lunch. I didn't even know our trucks had a Check Engine Light!!! I checked the Oil & Water and they were normal. Oil Pressure & Temp also seem normal.



Any thoughts on the reason for the Warning Light?



Probably Emissions! I'm certain that my Exhaust Particulate Filter or Urea level is low!



The light concerns me a 100% mechanical Cummins.



Tim "KEENO" Keen

 

[Greenleaf]

LOL... ..... They (the 1st Gen trucks) have a PCM. You probably have to check the codes by cycling the key etc. and reading the code numbers.



See what you find... ... .

 

[tugboatphil]

I unplugged the light on mine. There is no problem so big or complex, that it can't be ignored... . except maybe a cracked flexplate. :-laf

 

[Greenleaf]

Phil,



They didn't install a light for the "CHECK FLEX PLATE" cuz I "think" it's illegal to drive if you are hearing impared. Mentally impared, ok. But certainly not hearing impared.

 

[Sri Ram]

Not to be on topic or anything, but I don't recall seeing a check light in my 91's cluster when I've pulled the bezel. Was the light added later than the 91 mid-year introduction?

 

[Greenleaf]

No. But I "think" he is refering to the cluster. I don't have them memorized as to what they are.



Wait To Start

Brake

Anit-lock Brake

Water in Fuel



There is one that will never illuminate called LOW FUEL unless you run dry.



Is there more? Sorry, I almost never look at 'em. I'd have to dig out the manual. I cannot even say which one the PCM will flash to check the codes w/o looking at the book. There might be a lamp that says Check Engine somewhere..... How would I know? I just drive the thing. LOL

 

[Philip]

There is a check engine light. Cycle the ing switch three times. Leave it on the third time and it will flash the code for the problem on the check engine light. Watch it closely. The first code should be 12. This is start test. The next code is the problem your having. The last code should be a 55. This means end of test.



Let us know what code it throws at you.

 

[KEENO]

Thanks....

Thanks for the replies an banter Boyz!



FYI: The Check Engine Light is on the same IP Gage as the Temp Gage. Far left one of the three. I've never seen it come on either.....



Philip: Thanks for the insight of how to read the blinking Check Engine Light.



I'll Get 'er Done and git back with ya'll!



Tim "KEENO" Keen

 

[KEENO]

Code reading....

Philip & Gang... .



Obviously, I'm not very good at reading flasing codes. How does one read code?



Example: If it's a Code 12 (Start of Test)..... Will if flast 12 times or once, the pause, and flash two times?



Same for Code 55: (End of Test) 5 times, pause, and then 5 more times or 55 times?



I thought i figured it out when the Alternator wasn't charging, but I was told it could be the PCM.



KEENO

 

[btoscano]

Its possible the voltage regulator in the PCM has failed, or the crank position sensor on the front crank pulley has failed (or somehow moved to a distance other than 0. 050"). Those are 2 other reasons why the alternator might be charging, if the alternator is good.

 

[Philip]

It will flash then a pause to start the next number.