How to check if computer is bad.

10

Asked by Jun 22, 2013 at 09:45 PM about the Jeep Cherokee

Question type: Maintenance & Repair

I have a 2000 Jeep Cherokee Sport with a 4.0 that when the engine temperature reaches 208 degrees the engine rpm jumps up to 2000 - 3000 rpms, hoping you all could tell me why.  Also, how do you check the computer to see if it's bad?
Thanks for any and all information received.

5 Answers

you have a temp sensor that is giving errant info...think on this car it is more than a coolant sensor, it must measure air temperature too...this device an ambient air sensor should be replaced...how you check is with the OBD-II connector located three feet from your ignition switch...any autoparts store will read your codes for you or your could buy your own scanner for around twenty bucks~

2 out of 2 people think this is helpful.

kind of leaning towards a vacuum leak...may not be your ambient sensor...really need the diagnostics please~

10

I took it in and had it scanned, but it is not giving any codes so the scanner couldn't find anything.

1 out of 1 people think this is helpful.

you could start searching for a vacuum leak...one way is to use an unlit propane torch...hold it above the suspected leak and note the increase in rpms~ computers don't go bad...grounding and voltage to them goes bad~

1 out of 1 people think this is helpful.

the grounding to your ECM is tenuous at best...as they saw fit to put the 300 amp requirement on the same bus as the delicate 750 Ma requirement...very bad...electronics are delicate...starters are power hogs....a "fuzzy" ground connection translates to varying voltages and varying amperages (fuzzy power) which creates failure conditions....fortunately a SOLID connection to ground with a NEW battery will make it all better~ (should, in my experience)

2 out of 2 people think this is helpful.

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