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What is your question?
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What is your question?
Computer code from O'Reileys and AutoZone both read p1239.
1 Reply
This is a fuel pressure data monitored Powertrain Control Module (PCM) code. When the PCM detects any of a number of problems in the controlled fuel pressure it will go into limp in mode which causes power to shut down to the 40-45 MPH until the engine is shut off and restarted without the problem present. This code only comes up on the second time the PCM see's a fault in the system making it harder to pinpoint in diagnostics, to pinpoint the problem will take a skilled tech. There is a low pressure lift pump in the fuel tank that supplies fuel to the high pressure fuel pump at the cylinder head which in turn is controlled by the PCM to exact fuel pressure to allow the fuel injector's to spray directly into the combustion chamber. Any lack of electrical signals to and from the pressure duty cycle controlled fuel regulator, or the hi & low pressure fuel pump supply of fuel or electrical shorts to and from the PCM will cause the code and only on the second incident, it goes into limp in.
Thanks for getting back to me. I appreciate your insight. So, what would you guess be the problem? The fuel pump or sensor? Are you here in Tulsa?
I'm sorry to say there's no guessing on this code. Your dealing with a direct injection fuel system, to make that a little more understandable, a normal fuel injection system operates on a PSI of 35 to 55 depending on the fuel system needs. This high pressure system operates on 5 - 10 MPa (725. to 1450. PSI) because it injects fuel into the combustion chamber as the piston is creating maximum amount of pressure for the best combustion. Instead of a normal system that takes fuel into the intake manifold at almost no pressure with the air long before the compression cycle starts. That high pressure makes testing the fuel pressure not feasible. So your forced to use the readings from the PCM as it acquiring from the fuel sensor regulator which can be misleading making the testing harder. To troubleshoot this system take a driveability tech with a Tech 2 scanner (factory) and a good knowledge of electrical work. The manufacturer has a 35 step test process for this code which is exceptionally long and in the end it states if the problem is not found to replace PCM with a know good PCM, reprogram and retest. Adding to the testing is the fact the code is set only on the second incident and makes it much harder to track down unless it's happening almost every drive cycle. If the testing was to get's to this point you could be in for more than $1000. to $2000. for repairs. I would hope it to be an electrical short or a mechanical part wore out making it a much quicker repair. Yes I do owe a shop in Tulsa and Owasso. I myself run my Owasso shop, I'm a ASE Master Tech and do this kind of work and have the Tech 2 scanner but sorry to say I'm booked until the end of the month, for a quicker repair the dealer should be able to get to it this week. If not call me, Tim 918-371-1412. Also if you get it into the dealer and something doesn't sound right about their suggested repair work give me a call an I could give you some guidance.