2007 Chevy Tahoe P0615 and U0214 Codes: No Crank, Key Turns but Won't Start

The issue may stem from a faulty starter relay control circuit. Try swapping the starter relay with a known good one — for example, one not used by fuel pump or PCM — and test if the vehicle cranks. Use a test light to verify continuity and voltage during operation.

Have someone turn the key to the crank position while you place your finger on the starter relay. Listen for a click or feel any vibration — this can indicate if the relay is engaging properly.

Thanks for the tip! I’ve confirmed with a test light that all components are functional. The relay clicks clearly when in the crank position. I also have a Snap-on Solus Edge and standard test lights available. I swapped relays and verified they click — audible from inside the cabin.

Check for battery voltage at the starter solenoid’s 'S' terminal when the key is in the crank position. This will help determine if power reaches the starter directly.

I tested the starter while attempting to crank — even tapped it gently. The only voltage I observed was at the battery cable terminal. No voltage on other terminals during cranking. Jumping the starter with a flat-head screwdriver confirmed it works, so the issue is not in the starter itself.

Remove the starter relay and check its markings. Terminal 86 should receive battery voltage from the PCM during cranking — this should be hot when key is in crank position. Use a test light connected to negative battery terminal: touch positive terminal to verify it lights up. Then, touch terminal 86 while in crank position — it should illuminate. Next, connect the test light to positive and touch negative; then touch terminal 85 — it should light (indicating constant ground). Post your results for verification.

I’ve completed all these tests with a wiring diagram. Results: Terminal 85 has solid ground, Terminal 30 shows voltage only during cranking, Terminal 86 has battery voltage when key is in crank position. I jumped terminals 30 and 87 — the vehicle cranked successfully. My scanner also confirmed that ignition switch positions match run/crank states correctly. This strongly suggests a BCM (Body Control Module) issue — but I’d like to confirm whether there’s another possible root cause before replacing any modules.

If terminal 86 has battery voltage with the key in crank position and terminal 85 has constant ground, then the relay control circuit is complete. The PCM should send 12V to terminal 86 to initiate cranking. If no cranking occurs despite this, either there’s a broken wire or the PCM itself is faulty.

The ignition switch sends a signal to the BCM when the key is in crank position. The BCM then relays that signal to the PCM, which ultimately activates the starter relay control circuit.

Ah — I understand now. The PCM sends 12V to terminal 86 of the starter relay to initiate cranking. If no response occurs despite this signal, either there’s a broken wire in the control circuit or the PCM is defective. I’ll try testing with a known good wiring harness and verify the signal path next.

Yes — terminal 85 has constant ground. The PCM includes a voltage sensing circuit that detects current flow when battery voltage is applied to the control circuit. You mentioned terminal 86 shows battery voltage with key in crank position, and terminal 85 has solid ground. This confirms the signal path is present.

I’m a bit confused now — the relay markings and wiring diagram seem inconsistent. But based on your explanation, it makes sense: terminal 86 should be hot at all times (battery voltage), while terminal 30 is only hot during cranking. I’ve confirmed that terminal 85 has ground and lights up with test light. Terminal 30 appears to behave like terminal 86 — only active when cranking. Does this sound right? If not, I can share photos for clarification.

Yes — you're correct: terminal 86 should have battery voltage at all times, and terminal 30 should be hot only during cranking. Use a test light connected to ground to verify this behavior. Ensure the relay is properly marked.

Yes — that’s accurate.