2011 5.7 With Wireless Ignition - No crank/No Start

Good evening, a buddy I rent a room to is having problems with his truck that he uses for his landscaping company. The battery was overcharged for whatever reason (Altenator problems, regulator problems, computer problems) and he was left in a no crank no start condition after battery replacement. According to him, the dealership diagnosed and said it was an alternator. So I towed the truck home, replaced the alternator with one he supplied, charged the newish battery full, and began diagnosing the no crank no start situation. Dash, lights, and display work well. Key fob will unlock and lock doors, as well as send a signal for remote start. Sending a remote start command will beep the horn and the dash display will indicate that remote start is disabled use the key to start and reset. When the key is turned to the start/run position all the proper relays energize, except the starter solenoid relay. I can jump the relay/terminals in the fuse box and the engine spins with no start. Under normal circumstances I'd suspect the ignition switch, but I have little experience with these modern wireless ignition nodes. The fuel pump circuit is being grounded out by the computer or TIPM I'm assuming. With all components hooked up properly, I have 0 volts on both sides of the 20 amp fuel pump fuse. If I remove the negative battery terminal, and keep the positive connected, then measure voltage between the 20 amp fuel pump fuse and the negative battery post, I see a healthy 12v. As soon as the negative battery terminal makes contact with the negative post, my 12v reading at the fuel pump fuse dissipates. I'm not seeing any signs of antitheft being activated, or any other sort of immobilizer. I suppose overvoltage could have burnt up one or more of the modern electrical gadgets, or "burdens" I like to call them...

I'm under the impression that the PCM regulates the battery charging on this truck, via battery temp sensor and input voltage, but I didn't see a temp sensor wire under the tray at glance. The new alternator did have a sticker on it indicating that it was not internally regulated, but infact regulated by the computer. I'll cross that bridge after I get the truck to start. I appreciate any help, I'm stumped and I don't want to suggest throwing parts at it just yet. Lol.

WCM is a common failure, connections inside get loose. Try turning the key to the start position and while holding it in the start position wiggle the key up and down.

As to the temp sensor for the battery, your 2011 does not have that. Alternator output is controlled by the PCM.

Tach_tech said:

WCM is a common failure, connections inside get loose. Try turning the key to the start position and while holding it in the start position wiggle the key up and down.

As to the temp sensor for the battery, your 2011 does not have that. Alternator output is controlled by the PCM.

Click to expand...

Thank you for the information. I hooked up a more advanced obd scanner than what I was initially using and did a few tests. Long story short, the problem is related the the ASD relay/ecu/tipm if im not mistaken. The ECU is not grounding the brown/black wire in circuit k51 that terminates at ASD relay pin 86. Thus not allowing power to flow through the relay and out of the fused ASD relay outputs. I'm not having luck finding an ecu plug pin out that shows the brown and black wire at the moment. The wiring diagrams I have show the brown/black wire im mentioning, I have located it on the left most tipm plug and cross referenced on tipm pin outs. The ecu pin outs I do have, only show a brown/white asd related wire for some reason. I suppose the wire could change color between the two components. My next step is check the brown/black wire continuity between tipm plug and ecu plug once I have verified their termination location. Im assuming the ecu grounds the ASD via brown/black wire, I haven't necessarily confirmed it.

I have a post awaiting approval (new account) that should be in the tech section of the 4th gen forum, but basically TL;DR - I had the same occur in my 1500 last week!

Check pin 96 (driver side PCM connector - solid red wire) and probe it to get voltage. It should be battery voltage. If it doesn't get full battery voltage, you may have a break in your wire.

I had a break in my harness on this wire creating a situation where the error code was U0100 and key unlocked and locked truck, and windows would go up and down normally, but the truck would not crank or turn over, and the radio would be in anti-theft mode!

Fix was simply to cut the wire from the harness (delete it, leaving it in harness) and running a new 12V from the fuse (under fuse box) to the PCM connector (spliced in).

Check the red wire that goes between the ignition & module behind the small rear seat