Hello all. I’m new to the forum and am having an issue with my daughter’s 05 Envoy Denali with the 5.3L V-8 that has me ready to pull my hair out. My son-in-law and I removed the transmission at a friend’s shop Saturday to replace the rear seal on the engine. The exhaust pipe with the cats gave us the runaround trying to get them out but we finally got them. Replaced the rear seal and the transmission. When we attempted to start the engine Friday night after the job we got a no crank, no start issue when turning the key. Along with the no start, no crank was a P0335 Crankshaft Position (CKP) sensor circuit (Symptom 00) and a P0340 Camshaft Position (CMP) sensor circuit (Symptom 00) codes. No issues with no start, no crank before this rear seal job. This is not a DOD engine. I am not getting a security light.
We went back to the shop Sunday to begin troubleshooting. I did some research Saturday night after getting home and came across a couple of posts where guys have pretty much the same symptoms I have and they corrected it with a new ignition switch. Since that’s a fairly cheap, easy repair and seems to be quite the issue with these vehicles I installed a new ignition switch first. The engine started the first try and then went back to no start, no crank on the second try with only the CKP code this time.
Looking at the wires going to the CKP the section of the harness close to the starter the wires were hard and the insulation was pretty brittle. Looking further back in the harness we found all three wires with skinned insulation about 10 inches from the CKP connector. I figured we might have damaged these wires while we were wrestling the exhaust pipe out. I installed a new connector pigtail cutting and connecting one wire at a time being extremely careful to get the wires correctly pinned. Plugged the harness in, installed the starter, the engine cranked and started once then no crank, no start with CKP code.
My son-in-law has a zipper on the starter now. He must have had the starter out and back in at least twenty times. If the starter is out laying on the frame rail, turning the key will spin the starter EVERY time without logging any codes. Put the starter back in and about half the time the engine will start once without codes and then go back to no start, no crank with either both CKP and CMP codes or only the CKP code.
It started getting late Sunday, it was my buddies anniversary and we needed to get out of his shop and let him get home to his wife so as much as I dislike the practice I pulled out the parts cannon. I have replaced the;
Ignition switch having removed and reinstalled several times to be sure it was in correctly
CKP sensor and pigtail connector
CMP sensor (once we found it at the front of the engine) along with the CMP intermediate harness
Today I had the truck towed to the house. I was planning to run new harness wires from the PCM to the CKP but I found a tutorial online to check the CKP circuit and it checks out good. I have 12V at the CKP (having back probed the connector) and voltage on the signal wire changes from 10.5V to .5V as you turn the crankshaft with a ratchet and socket.
Sunday we swapped the Starter and Powertrain relays with no change in symptoms. Today I verified continuity from terminal 87 (the terminal in the fuse box) of the starter relay to the start terminal on the starter. I also verified 12V at terminal 30 at the relay. However, when I jumper 30 to 87 I get no crank, no start. I jumpered Battery + to terminal 87 and again, no crank, no start. Again, these were the terminals in the fuse box.
I have verified inputs to and outputs from the ignition switch.
Red and red/white are hot at all times.
White is hot in Accessory, Run and Start.
Orange is hot in Run.
Yellow is hot in Start.
Brown is hut in Accessory and Run.
Pink is hot in Run and Start.
One other tidbit. The truck does have an Omegalink remote starter from Caralarm that I installed 3 years ago and has been working flawlessly since the install. When I try to start the truck with the remote start I can feel it energize the starter relay but again, no crank, no start and the CKP code.
This one has me stumped. Why does the starter spin every time when laying on the frame rail but very sporadically when bolted to the engine? Why does the CKP sensor (and sometimes the CMP sensor) throw codes when the starter won’t even click, much less move the crankshaft, but never code when the starter is spinning on the frame rail? I was thinking maybe an EMI issue with the sensors since the CKP harness runs right beside the starter but I have laid the harness and sensor ON THE STARTER laying in the frame rail and it doesn’t code when the starter spins, only when the starter is bolted to the engine and DOESN’T spin! Why doesn’t the starter spin when I jump the Starter relay terminals with 12V from the fuse box or the battery?
I apologize for the mini novel here but wanted to give as much information as I could to answer as many questions as I could from the get go. I’m hoping someone can offer me some insight.
We went back to the shop Sunday to begin troubleshooting. I did some research Saturday night after getting home and came across a couple of posts where guys have pretty much the same symptoms I have and they corrected it with a new ignition switch. Since that’s a fairly cheap, easy repair and seems to be quite the issue with these vehicles I installed a new ignition switch first. The engine started the first try and then went back to no start, no crank on the second try with only the CKP code this time.
Looking at the wires going to the CKP the section of the harness close to the starter the wires were hard and the insulation was pretty brittle. Looking further back in the harness we found all three wires with skinned insulation about 10 inches from the CKP connector. I figured we might have damaged these wires while we were wrestling the exhaust pipe out. I installed a new connector pigtail cutting and connecting one wire at a time being extremely careful to get the wires correctly pinned. Plugged the harness in, installed the starter, the engine cranked and started once then no crank, no start with CKP code.
My son-in-law has a zipper on the starter now. He must have had the starter out and back in at least twenty times. If the starter is out laying on the frame rail, turning the key will spin the starter EVERY time without logging any codes. Put the starter back in and about half the time the engine will start once without codes and then go back to no start, no crank with either both CKP and CMP codes or only the CKP code.
It started getting late Sunday, it was my buddies anniversary and we needed to get out of his shop and let him get home to his wife so as much as I dislike the practice I pulled out the parts cannon. I have replaced the;
Ignition switch having removed and reinstalled several times to be sure it was in correctly
CKP sensor and pigtail connector
CMP sensor (once we found it at the front of the engine) along with the CMP intermediate harness
Today I had the truck towed to the house. I was planning to run new harness wires from the PCM to the CKP but I found a tutorial online to check the CKP circuit and it checks out good. I have 12V at the CKP (having back probed the connector) and voltage on the signal wire changes from 10.5V to .5V as you turn the crankshaft with a ratchet and socket.
Sunday we swapped the Starter and Powertrain relays with no change in symptoms. Today I verified continuity from terminal 87 (the terminal in the fuse box) of the starter relay to the start terminal on the starter. I also verified 12V at terminal 30 at the relay. However, when I jumper 30 to 87 I get no crank, no start. I jumpered Battery + to terminal 87 and again, no crank, no start. Again, these were the terminals in the fuse box.
I have verified inputs to and outputs from the ignition switch.
Red and red/white are hot at all times.
White is hot in Accessory, Run and Start.
Orange is hot in Run.
Yellow is hot in Start.
Brown is hut in Accessory and Run.
Pink is hot in Run and Start.
One other tidbit. The truck does have an Omegalink remote starter from Caralarm that I installed 3 years ago and has been working flawlessly since the install. When I try to start the truck with the remote start I can feel it energize the starter relay but again, no crank, no start and the CKP code.
This one has me stumped. Why does the starter spin every time when laying on the frame rail but very sporadically when bolted to the engine? Why does the CKP sensor (and sometimes the CMP sensor) throw codes when the starter won’t even click, much less move the crankshaft, but never code when the starter is spinning on the frame rail? I was thinking maybe an EMI issue with the sensors since the CKP harness runs right beside the starter but I have laid the harness and sensor ON THE STARTER laying in the frame rail and it doesn’t code when the starter spins, only when the starter is bolted to the engine and DOESN’T spin! Why doesn’t the starter spin when I jump the Starter relay terminals with 12V from the fuse box or the battery?
I apologize for the mini novel here but wanted to give as much information as I could to answer as many questions as I could from the get go. I’m hoping someone can offer me some insight.