2006 Trailblazer wont start--intermittently cranks--relays-fuel pump not working

ghf32694

Original poster
Member
Feb 9, 2013
8
My trailblazer suddenly won't start. Turn the key and may crank, release the key and all lights are on but will not crank. Remove the key and wait a few minutes and will try to crank until the key is released and then nothing. Can't hear fuel pump kick in or that relays are working. Can jump across starter relay and engage starter without any problem. Had this problem a year ago and all of a sudden started running. The ignition switch has been replaced before. Guessing that could be the problem. Does anyone have any ideas or steps to test the ignition switch. Thanks for any help.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Put your voltmeter on the following wires to check the ignition switch functionally:

RED on the ignition switch is 12V, fused by underhood fuse #34, and feeds the following three circuits:

White is hot in ACCY, RUN, START
Orange is hot in RUN
Yellow is hot in START

RED/WHITE is another 12V, fused by underhood fuse #36, and feeds two circuits:

Brown is hot in ACCY, RUN
Pink is hot in RUN, START
 

ghf32694

Original poster
Member
Feb 9, 2013
8
Thanks Roadie... I checked and the proper voltages are leaving the ignition switch as you listed. What else should I look for? I can turn the key and it will crank, release the key and it won't crank again for a few minutes but all the gauges and everything light up.
 

ghf32694

Original poster
Member
Feb 9, 2013
8
One more detail the fuel pump is working. If I release the pressure on the fuel rail, I can hear the fuel pump turn on and the fuel rail is pressurized again. Thanks
 

RayVoy

Member
Nov 20, 2011
939
If pump appears to be working, your fuel delivery is probably ok (you could try a squirt of either just to be sure). If still no go, it must be air, or spark.

Check air filter and air tube for restrictions.
 

CaptainXL

Member
Dec 4, 2011
2,445
If you can jump across the starter relay and it starts right up then that's definitely the problem. Remember the axiom KISS.
 

ghf32694

Original poster
Member
Feb 9, 2013
8
Sorry, I should have been more specific. I can jump across the relay and engage the starter but the trailblazer still doesn't start. I went and rented a code reader. Here is a list of all the codes it gave me. P0607, P060D, P060E, P2610 and P0463. I looked up each of these on line but not really for sure what direction to go with it. It looks like most of the codes reference the ECM-PCM and the Fuel Level Sensor A circuit. I erased the codes, took off the battery cables to let the PCM reset, turned the ignition on but didn't try to start the engine....the result was Codes P0606, P060D and P060E. After this I waited until it felt like allowing the starter to engage from the ignition. It still would not start and the results on the code reader was the list of 5 codes I first mentioned above. I truly appreciate the help and suggestions.
 

CaptainXL

Member
Dec 4, 2011
2,445
ghf32694 said:
I looked up each of these on line but not really for sure what direction to go with it.

So your not confident in fixing this yourself even after looking at all the free tons of info already available at your fingertips on the Internet? Plus you are not mechanically inclined? If thats the case my suggestion would be to take it into a couple shops to get a quote first.
 

ghf32694

Original poster
Member
Feb 9, 2013
8
CaptainXL that is not the situation at all. I love a good challenge and I have spent most of the past week or so looking for answers and testing items. I have read thru hundreds of threads and tried just about any troubleshooting tip I could. I would much rather fix it myself and have that satisfaction. I came to this forum looking for some good friendly advice by others who may have went down the same path. I thought someone may be able to shed some light on the combination of engine trouble codes. One other item I checked was the grounds, and they have all read about .2 ohms.
 

CaptainXL

Member
Dec 4, 2011
2,445
Im specifically talking about the codes you just pulled up today. There is no way you have read 100's of threads about your codes and not come up with something.

You've tested each of these?

A P0607 could be caused by one or more of the following:

Loose ground terminal on PCM/ECM
Dead or defective (12V main) battery
An open or short in the power or ground circuit
Loose or corroded battery terminals
Failed PCM/ECM

I would start simple and make sure the battery cable terminals are free of corrosion and the battery bolts are not stripped. This sounds like an amperage problem and not a voltage problem. Replace battery as well if old or unsure of its condition.

Also, has anyone recently remove/replaced or in general worked on anything PCM or electrical related with the vehicle within the past 2 or 3 years?
 

ghf32694

Original poster
Member
Feb 9, 2013
8
I think sometimes I read too much and go off in a lot of different directions trying to solve the problem. It seemed in reading that a large number of issues were related to loose or bad grounds. That is what I have spent most of the day working on. I took apart any ground I could find and cleaned them up and tightened them back down. I then tested the grounds with reference to the negative battery terminal and they were good. The battery is about a year old and the problem started last week after a cold night and the key was left in the ignition turned to accessory. Got in that morning and it would barely crank. I took the battery out and charged it. Load tester showed the battery was good. When I put it back in I had this mess. I am still tracing down the power circuits. The ignition switch was replaced 2 summers ago when it did this very same thing and I checked everything out. Couldn't find the problem was getting ready to give up, went out and hit the key and it started. It had been running great ever since then. That is what lead me to believe it was a loose ground or high open in a wire. Sorry to ramble and I appreciate the advice.
 

CaptainXL

Member
Dec 4, 2011
2,445
I'm still leaning towards corroded battery cable terminals or stripped battery bolts.

These checks are part of an actual TSB for our vehicles so its vital you check them.

Checking grounds won't do any good if its an amperage issue.
 

RayVoy

Member
Nov 20, 2011
939
Guys, the OP tells us that the engine will crank. That takes current. I suggest there is nothing wrong with the battery cables.

The engine will spin, it does not fire. It is missing fuel, spark, or air.

I'm not ruling out a poor ground, and, or, a poor hot connection somewhere, there may be a loose/poor connection at the pcm. PCM grounds are known to fail (a lot of PCMs have been unnecessarily replaced because the ground was poor.

Did the CEL come on when this problem started, or has it been on for awhile?
 

ghf32694

Original poster
Member
Feb 9, 2013
8
Checked the battery with a load tester, it's good. Battery connection are all tight and good. Noticed the throttle body was pretty dirty. Took it off and cleaned real good. Engine would fire one time and then just crank. After releasing key, all lights came on but no crank. Pull PCM fuses and put them back in and engine would crank again but not fire. Trying to figure out why the PCM needs to reset to allow the engine to crank.....it's getting frustrating
 

CaptainXL

Member
Dec 4, 2011
2,445
You have checked pretty much everything including grounds and power to PCM. So there is really nothing left.

The code P2610 is not good. I read up on a couple other forums and it states that this may be a programming issue with the PCM. What you can do is try and get the PCM reprogrammed and see if that fixes the problem. Failing that then the PCM might need to be replaced.

But before doing any work or guessing and considering the issues you are having I would get a professional diagnostic done at a reputable shop or dealership. Yes, it might cost a few coins but in the end you will have the satisfaction that you had it fixed right the first time.

Overall I don't think this is an issue that can be fixed with advice in a forum on the Internet very accurately. So that's my .02. Good luck!
 

mrphoenix80

Member
Jan 1, 2013
251
All the codes you have are in 1 diag tree except the fuel level sensor. But if I follow the tree its 3 steps long. Is this code set? Check power and ground. did you fix it? yes = good. No = pcm replacement.

So if you put in a PCM it still needs to be programed by someone with access(dealer). So I think your at the end of your road. Good luck getting it up and running.

And as for the level sensor code. Do you trust a PCM that is telling you its braindead?:undecided:
 

ghf32694

Original poster
Member
Feb 9, 2013
8
Thanks for the advice from everyone. I am going to run thru the grounds one more time and then call it quits. Kills me to give up on something but I got to get it back on the road.
 

CaptainXL

Member
Dec 4, 2011
2,445
ghf32694 said:
Thanks for the advice from everyone. I am going to run thru the grounds one more time and then call it quits. Kills me to give up on something but I got to get it back on the road.

One final idea. Have you actually taken the connectors off the PCM and removed it to inspect?

P0606 is PCM / ECM Processor Fault. So yeah, what mrphoenix said.
 

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