gsjimmy

P1336 code on an otherwise stock LM7 5.3, can't clear the code. System remains in open loop. Already have run all the connections, grounds. This is a 2004 5.3 that was DBW and now converted to DBC. Using the stock ECU set-up for the swap. Code appears in the current diagnostic and in stored history. Have tried both the hand held and the Snap-on Tech 2 set-up at a buddy's shop. Have replaced the sensor 2x, double checked that connection, rechecked the ECU (that's a process as it's mounted up high in the dash). No broken wires found.

So at this point, is it possible that the ECU is having "issues". Thinking of getting another 0411 ECU to swap it out as I'm out of ideas at this point.

Anyone else dealt with this issue?



'69 GS California
2004 LM7 5.3 with 177,000 miles
2004 4L60E trans
Speed engineering long tube headers into 2.5 in true dual exhaust (T/A Performance)

455 Stage 1 is crated up in the shop!

gsjimmy

So here is what I've tried so far:

Grounds (2x)

Wiring, new harness, no abrasions, cuts. Plugs and pins appear to be fine

Mass Air Flow meter replaced - gave me a code about voltage reference. Put on a new unit after 2 bad used ones. Still codes until the car is rev'd to excite the wire reading. Then is fine.

Looking for a tuner in the Madison WI area to remove the P1336 from the ECU. Researched and found it is a secondary misfire reading. Not really needed. Let me know if that is not true.

May look at a software program as well, would be nice to be able to shut off any unneeded items for a swap situation. Any recommendations? Stuff I deal with is all DBC

Jim

tblentrprz

P1336 is crank sensor error. What changed since it last functioned OK? 24x crank reluctor and sensor installed? Use AC Delco sensors. Aftermarket can/will cause flaky output signals. Did you do a crank relearn? Did it pass? Lastly, scope CKP sensor output at sensor and PCM. If looks good.

B52bombardier1

Hello,

I have been dealing with misfires on my LM7 and did all that you did and that has been suggested above. But my problems got fixed this past weekend with a different PCM. This was my first PCM failure in four years of dealing with LS engines and I always thought that a PCM failure was highly unlikely.

But sure enough, they do fail and my bad box is comfortably resting in the trash can. I can now go back to the junk yard and grab another one for 32 bucks and flash it with LS Droid for as they say . . . "free, free, free, free" . . . - no HP Tuner credits required.

Rick