No Crank, No Start Final Issues - What Else Could It BE???

Forum members...As I know this topic has been brought up before, I haven't found one to go this far into diagnosis.

2004 Yukon SLE 5.3, 220k miles.

No crank, no start has been going on sporadically for the last month. Following all information I could find, I started replacing items one at a time. First, the battery and alternator tested fine, all grounds and positive cables to battery, alternator, starter, and frame are in good working order. Every time I replaced something, vehicle would work for a day, then wouldn't start again. Sometimes it sat over night, sometimes it sat for a few minutes. As with the other write ups, all lights work, no other electrical issues noted.

Items replaced so far:
Starter relay
Ignition relay
Crank fuse
Every fuse, under hood and under dash, marked IGN
Ignition switch
Starter

What else could it be? I guess I'll replace the key cylinder...I can't think of anything else?

Suggestions?

Did you find anything for your issue? I just bought a 95 tahoe and the previous owner bypassed the ignition and put a push start button on it. As long as you have the key in the ignition and turned to the on position it will start. I just don' like rigged work and want it the right way

rfried said:

Forum members...As I know this topic has been brought up before, I haven't found one to go this far into diagnosis.

2004 Yukon SLE 5.3, 220k miles.

No crank, no start has been going on sporadically for the last month. Following all information I could find, I started replacing items one at a time. First, the battery and alternator tested fine, all grounds and positive cables to battery, alternator, starter, and frame are in good working order. Every time I replaced something, vehicle would work for a day, then wouldn't start again. Sometimes it sat over night, sometimes it sat for a few minutes. As with the other write ups, all lights work, no other electrical issues noted.

Items replaced so far:
Starter relay
Ignition relay
Crank fuse
Every fuse, under hood and under dash, marked IGN
Ignition switch
Starter

What else could it be? I guess I'll replace the key cylinder...I can't think of anything else?

Suggestions?

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Stop throwing parts at it! The ignition lock cylinder (where you put your key in) has absolutely nothing to do with the start system electrically. It is purely mechanical and moves a rod downward/upward along the steering column which moves the ignition switch into the correct position.
You most likely have an electrical problem and need a electrical schematic for your system, a person that knows how to use a voltmeter and the vehicle acting a fool (its hard to troubleshoot a vehicle when it aint broke currently). If you know how to use a voltmeter then I/We can guide you through the schematic. First check is cut the electrical system in half and rule out one half or the other.

We need to find out exactly what its doing first. Is it failing to crank or failing to start after cranking?

6speedblazer said:

We need to find out exactly what its doing first. Is it failing to crank or failing to start after cranking?

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Says right in the title of the thread "No crank". Of course there will be a no start condition since the engine isnt even spinning over because of the no crank.

rockola1971 said:

Says right in the title of the thread "No crank". Of course there will be a no start condition since the engine isnt even spinning over because of the no crank.

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says right in the title no crank no start which can be two completely different problems. hell half the time people bring me vehicles they will say it wont crank over and they are meaning it wont start. Not everyone is versed in car terminology, which is why i asked for verification. just trying to get everyone on the same page.

with that being said.

go to the parts store and get a test light. 5 bucks at harbor freight even.

next time you get a no crank condition. test for power at the solenoid power terminal on the starter. Hook the ground clamp of the test light to a solid ground. have someone hit the key, and with the key still in the "crank" position. see if you have power at the solenoid power wire. Its the smaller of the two wires on the starter and is typically purple in color.

after you verify that, we can move up the chain as needed and verify components.

6speedblazer said:

says right in the title no crank no start which can be two completely different problems. hell half the time people bring me vehicles they will say it wont crank over and they are meaning it wont start. Not everyone is versed in car terminology, which is why i asked for verification. just trying to get everyone on the same page.

with that being said.

go to the parts store and get a test light. 5 bucks at harbor freight even.

next time you get a no crank condition. test for power at the solenoid power terminal on the starter. Hook the ground clamp of the test light to a solid ground. have someone hit the key, and with the key still in the "crank" position. see if you have power at the solenoid power wire. Its the smaller of the two wires on the starter and is typically purple in color.

after you verify that, we can move up the chain as needed and verify components.

Click to expand...

I would cut the circuit in half coming right off the ignition switch. But his symptoms fo fit the criteria for a starter solenoid getting ready to die.
And dont "hit the key", youll bruise your knuckles. Terminology! hahahahaha

Sorry for bringing up an old thread, but this seemed to be the closest to what I am experiencing.


So I am having the same symptoms. 2004 Yukon with a 5.3, 2WD. Truck ran fine, then disconnected the battery for a few weeks, though I had the battery on a charger. Battery is fully charged and in good condition.


Once the battery was reinstalled, the truck will not crank or turn the fuel pump on. I can't see if it is a VATS issue, as the previous owner sold the gauge cluster.


I have tested all the fuses, and they are good. When the key is turned on, lights, HVAC blower, radio, etc., come on, but nothing is activating the starter or pump relays. Both relays have power at terminal 30. If I hot wire to terminal 87 on each relay, the pump and starter both work.


Crank 10amp fuse has power on both sides when key is turned to the start position.


Tried the VATS relearn process, but that did not help. Hard to know if I did it correctly without the Security warning on the cluster.


Held the key to start position and moved the shifter among locations to test neutral safety switch.


Hooked up an HPTuner MPVI2 to the OBDII port, and it will not connect. OBDII port does have power at 16 and ground at 4 and 5.


Any insights would be appreciated.


Thanks.

I hate to say it, but you kind of need a cluster at this point. Barring that, a Tech2 scanner to find out what the trouble code(s) is/are.

HooptieHeaven said:

Hooked up an HPTuner MPVI2 to the OBDII port, and it will not connect. OBDII port does have power at 16 and ground at 4 and 5.

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I would look into this issue. If there is communication trouble on the serial data line I don't think the truck will crank. Proper communications between the PCM and BCM are essential. Have any other code readers or such that you can use to test for communications?