Code p2509

[JPitha]

Well, it happened again. Around 0 deg temp, made it about 25 miles and the truck acts like it is starving for fuel then quits running. I am using power service additive so I have a hard time believing that it gelled up. While waiting for the tow truck, I decide to check for a code. pull up p2509. Get home and get on this site to find out what it means. Found post that said to disconnect the batts for 10 mins. Do this after paying $112 for the tow and the truck starts right up. Anybody know the real cause for 2509 ?? Don't really want to take it to the dealer if I don't have to.

 

[rbattelle]

From page 248 of the powertrain diagnostics manual:



P2509 - Powerdown Data Lost Error

When Monitored: continuous - key on or key off

Set condition: Loss of voltage detected at the ECM for a calibrated amount of time.



Possible causes:

-Poor connections at the batteries

-Low battery voltage

-Open fused B+ to ECM

-Open ground circuit

-Battery + shorted to other circuits

-Return circuit shorted

-Battery + shorted to ground

-Intermittent condition (they all say this).



There are 7 separate diagnostics tests for this code, but I'm not typing them all out here. I recommend connecting a voltmeter to the ECM power pins:



On connector C1 (the one with the polarizing pins at the top of the connector), pins 25, 27, 42, and 43 should all be +5v.



On connector C2 (the one with the polarizing pins on the bottom side of the connector), pins 20, 30, and 40 are fused B+. I recommend hooking a volt meter to that and monitoring it yourself.



Or, take it to the dealer and make them fix it.

 

[JPitha]

Thanks rbattelle, I'll do the voltmeter thing this week. will also load test the batts. JP