I have an interesting scenario that just developed and I'm trying to see if I can diagnose and fix it myself before taking her to the shop. While driving home from work yesterday, it felt like the tranny slipped briefy while at around 5000 RPM's and then proceeded just fine. Pulled up to a red light and when it tured green, again, felt like slippage in the tranny (Which I doubt as it was just rebuilt in FEB). After the second time, it set the code. I've been looking into/trying to find out what all is on this 5 volt circuit 2 and have gotten mixed answers. On another note, just noticed a leak around my water pump that wasn't there last week (I replaced my brake lines with stainless steel lines ) and I don't know if that could be causing problems. No overheating or anything, just a small mess.

I tested the A/C Pressure harness already. One reading was 4.9 volts and the other was 4.6. I imagine 4.9 was the reference voltage, but I have no idea if the other one was in the correct range. Read that these things shouldn't fluctuate more than about 0.2 volts if everything is working properly, but I am no certified mechanic. Going to try to track down more stuff today if anyone has any suggestions.

Helpful info, it's the SS LS4

 

P0651 refers to a 5 volt reference signal is either too high or too low at one or more sensors. Check the wiring harness making sure the connectors are clean/tight. Also check the harnesses that plug into the PCM. Do a continuity test on the harness to make sure there isn't an open or short in the wiring. It could also be a shorted sensor. Worst scenario your PCM is defective.

 

Yeah, that's what I'm working on. I'm just not entirely certain what all is on that circuit. I know it's definitely not a bad battery, still managing to push around 1000watts of pure audio bliss lol. I'm going to check the wires that go by the ABS module as well as I did manage to leak fluid down all over stuff in there. I suppose that could have been bad for it.

 

Any liquid that penetrates the connector could definitely cause a short. I would spray the connector with electronics cleaner, then pull it apart and clean the inside also.

 

The only other note that I forgot to mention is that once it has cooled off, the problem takes a little longer to manifest. It actually stalled in my driveway, and when I cranked it back up, the crank time was noticeably longer however it did start again. Hopefully it's just a sensor or dirty connection.

 

I hate electrical problems. Just gonna say. Been fooling around with this thing for the better part of a day trying to find the problem :/

 

I am now leaning towards crankshaft position sensor. Tried a few different methods when nothing else appeared to be wrong. When it acts up, the first thing that happens is it feels like the tranny slips. Then, the tach will either bounce around a little bit or just go out altogether. If I keep my foot off the gas and let it roll to a stop, shut it off and then attempt a restart, it cranks and may or may not turn over. Do this a few times and you finally get the CEL and code P0335. If I don't immediately stop and instead apply gas after feeling the hesitation, I get service TC/Reduced engine power and P0651.

 

Well, definitely wasn't the Crank Sensor. Should have known. After removing the exhaust manifold and breaking some good old plastic parts and losing other bolts, I only accomplished me sleeping a little harder lol

Putting her in the shop tomorrow. A guy I talked to at the dealership when I was picking up parts thinks it's going to be the throttle body. I guess we'll see!

 

If you haven't taken it to the shop yet double check the wiring at the throttle body plug. They have been known to break wires (but not noticeable because of the insulation). Try wiggling and pushing the connector together with the engine running. A plug is a lot cheaper to replace then a throttle body. Another place to double check is the connector on the Throttle Actuator Control. Make sure the connection is tight and the seal (holds plug in connector) is intact.

 

When you find out what it is put it here. Other members need to know who come up with the same issue. Thank and good luck.