Code P0508 will not go away

Tiny
LAKEHILT
  • MEMBER
  • 2004 JEEP LIBERTY
  • 3.7L
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 105,000 MILES
Been getting a code for Idle Air control circuit low- P0508 on my vehicle. IAC was changed and rewired along with the PCM being changed, throttle body was cleaned and changed TPS. Code was cleared ran great for 5 days then code reappeared along with a whistling noise and it doesn’t want to start sometimes so I have to disconnect battery and it will start after. Running out of options because after all that it still isn’t fixed. Need help as I can’t afford to take it to a mechanic. Please help!
Friday, November 22nd, 2019 AT 10:11 AM

6 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Here is the testing for this code. I understand it appears you covered everything but clearly we are missing something.

Let's run through this test and see what turns up. Depending on the wiring that you did I suspect there is a connection issue.
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Friday, November 22nd, 2019 AT 5:37 PM
Tiny
LAKEHILT
  • MEMBER
  • 4 POSTS
Will run through test today and get back to you. Thanks!
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Saturday, November 23rd, 2019 AT 6:43 AM
Tiny
STEVE W.
  • MECHANIC
  • 14,490 POSTS
Check for a vacuum leak as well, a whistling noise would be what a leak would indicate. A quick spray of starting fluid or carburetor cleaner would help track it down.
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Saturday, November 23rd, 2019 AT 7:35 AM
Tiny
LAKEHILT
  • MEMBER
  • 4 POSTS
Thanks Steve, will check for that as well!
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Saturday, November 23rd, 2019 AT 8:10 AM
Tiny
LAKEHILT
  • MEMBER
  • 4 POSTS
Did all checks on IAC and also checked for vacuum leaks. There is no issue with either. I checked fuel pressure and it’s high around 62 PSI looking like I need a new fuel pressure regulator. Could this have caused the IAC code?
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Saturday, November 23rd, 2019 AT 10:55 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Assuming you have a JTEC controller then you are correct that it is a bit high.

However, that is highly unlikely that it caused the IAC code. Do you have a scan tool to see what the MAP is reading?
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Saturday, November 23rd, 2019 AT 8:03 PM

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