P0237 no boost code
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Joined: Mar 2004
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P0237 no boost code
I have a 99 F550 with the 7.3 that won't get above 45mph and is throwing a low boost code. The turbo only has 6,000 miles on it, but i took it off and checked it out. Everything looks good. I can't hear any leaks, and I checked all 6 rubber boots everything looks good. With my scan tool hooked up i drove it around and with the pedal to the floor the most my IPR would show was 42%. Could that be my problem? I appreciate any help or suggestions.
Post Fiend
Joined: Nov 2007
Posts: 9,549
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From: Payson, AZ
Check the small black hose from the bottom of the spider to the MAP (Manifold Absolute Pressure) sensor. If that hose is off the MAP can't read boost. If the MAP sensor is good the scanner should be able to read ambient baro pressure with just the key on. If it doesn't the MAP sensor is bad or there is a connector or wiring problem. At sea level it should read about 14.7 PSI. I don't know if the PCM will go into a limp mode for lack of boost but that might be why you are limited to 45 MPH.
Post Fiend
Joined: Feb 2007
Posts: 14,541
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From: Dallas-Ft. Worth
I doubt is a sensor issue -- I forgot to plug in my boost sensor and it drove fine, but threw a code (same one, I believe). Sounds like you actually have no boost. This is where a real, separate boost gauge pays off.
Any other symptoms besides won't go over 45 mph? What did you read the codes with? IPR is perfect for stock tuning. I assume if you look at the boost reading from the PCM is shows nothing, right? When I read the MAP mine shows real boost numbers, not baro -- the backpressure sensor shows baro however...
Any other symptoms besides won't go over 45 mph? What did you read the codes with? IPR is perfect for stock tuning. I assume if you look at the boost reading from the PCM is shows nothing, right? When I read the MAP mine shows real boost numbers, not baro -- the backpressure sensor shows baro however...
Post Fiend
Joined: Nov 2007
Posts: 9,549
Likes: 14
From: Payson, AZ
There are 2 readings you can look at, at least with AE. Absolute and guage pressure. Gauge pressure is minus baro. Absolute is baro plus boost. Both readings come from the MAP. Yes, the EBP sensor will also read baro with KOEO.
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