What this code means
P0351 may indicate a problem in an ignition coil control circuit where the commanded circuit state and the actual circuit response do not agree.
What the vehicle may do
- The vehicle may run rough or misfire.
- The check engine light may come on.
- The concern can be intermittent if wiring or connector contact is involved.
Possible fault areas
- Possible coil control circuit wiring, terminal, or connector faults.
- Possible coil ground or ignition feed concerns.
- Possible ignition coil concern.
- Possible control module side circuit concern.
Diagnostic path
Opening context
On this 2019 to 2025 Chevrolet Silverado 1500 with the 5.3 gas engine, P0351 is an ignition coil control circuit code. In plain terms, the engine control module may be commanding an ignition coil circuit one way and seeing the circuit respond another way. The truck may run rough, misfire, hesitate, or turn the check engine light on. Broadly, this can involve the coil control circuit, the coil ground side, the ignition feed, wiring, terminals, connectors, or the control module side of the circuit. If other codes are present, check what they mean first, but keep this diagnosis focused on the P0351 coil control path.
Start with verification, not parts
Before getting into circuit testing, start with the basic system checks and follow a structured diagnostic approach. Then run the engine and look at the ignition coil control circuit test status parameters on the scan tool. For this diagnostic path, the high voltage, low voltage, and open test status parameters should read Not Run or OK. If any of those are not in that state, move into circuit testing instead of guessing at the coil.
Wiggle test and reproduce the fault
If the scan data looks normal, keep the engine running and wiggle the harness and connectors at the ignition coil and the engine control module. The same scan tool parameters should stay at Not Run or OK. If the status changes while you move the harness or connectors, repair the wiring, terminals, or connector issue as needed. If it still stays normal, reproduce the operating conditions for the monitor. The engine has to be running, ignition voltage has to be Greater than 11 V, and the monitor runs continuously after those running conditions are met. You can also reproduce the captured conditions from the stored data. After that, verify P0351 does not reset. If it does not reset, the verification is all OK. If it resets, continue into circuit testing.
Begin circuit testing with power down and ground integrity
For circuit testing, turn the ignition and vehicle systems off, and disconnect the ignition coil electrical connector. Be aware that it may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference continuity test can be made. Start at ground circuit terminal 1/A to ground. You want less than 10 Ω. If it is 10 Ω or greater, disconnect the ground connection and check from ground circuit terminal 1/A at the component harness to the other end of the circuit at the ground terminal. That check should be less than 2 Ω. If it is 2 Ω or greater, repair the open or high resistance in the circuit. If it is less than 2 Ω, repair the open or high resistance at the ground connection.
Check for an unwanted path to ground
If the ground check is good at less than 10 Ω, turn ignition on with the vehicle in service mode. Put a test lamp between control circuit terminal 3/C and B+. The lamp should not turn on. If it does turn on, shut the vehicle off, remove the lamp, disconnect the engine control module connector, and test control circuit terminal 3/C at the component harness to ground. The expected result is infinite resistance. If resistance is less than infinite resistance, repair the short to ground in the circuit. If the circuit shows infinite resistance, the diagnostic path supports replacing the engine control module.
Check for an unwanted voltage feed
If the test lamp does not turn on, remove the lamp, run the engine, and look at the ignition coil control circuit high voltage test status. It should be Not Run or OK. If it is not in that specified state, shut the vehicle off, disconnect the engine control module connector, and test control circuit terminal 3/C at the component harness to ground. The voltage should be less than 1 V. If it is 1 V or greater, repair the short to voltage on the circuit. If it is less than 1 V, the diagnostic path supports replacing the engine control module.
Command the circuit and prove continuity
If the high voltage test status is already Not Run or OK, turn the ignition and vehicle systems off. Connect a 3 A fused jumper wire between control circuit terminal 3/C and ignition circuit terminal 4/D. Then run the engine and verify the high voltage test status changes to Malfunction. That proves the circuit can be driven into the expected fault state. If it does not show Malfunction, turn the vehicle off, remove the jumper, disconnect the engine control module, and check continuity from control circuit terminal 3/C at the component harness to the other end of the circuit at the control module harness. That circuit should be less than 2 Ω. If it is 2 Ω or greater, repair the open or high resistance in the circuit. If it is less than 2 Ω, the diagnostic path supports replacing the engine control module.
Coil and spark check
If the high voltage test status does change to Malfunction with the fused jumper in place, the path moves to testing or replacing the ignition coil. Component testing comes after circuit testing, not before it. With the ignition and vehicle systems off, disconnect the spark plug wire at the spark plug and install the J-26792 ignition spark tester between the spark plug wire and ground. Run the engine and verify there is spark at the tool. An erratic or weak spark counts the same as no spark. If there is no spark, replace the ignition coil. If spark is present, that component test is all OK.
Verification and takeaway
After the repair, keep verification separate from the testing work. Verify the repair and confirm P0351 stays gone under the same kind of operating conditions that allowed the code to run. The takeaway is simple: prove the ground, prove the control circuit is not shorted, prove the circuit can be forced into the expected scan tool response, and only then condemn the coil or control module where the diagnostic path supports it. For more diagnostic training, visit stepdiagnostics.com.
Final check
P0351 is best approached as an electrical circuit diagnosis: verify the scan data, stress the harness, test the ground and control circuit, then verify the repair.
For more guided automotive diagnostics, visit STEP Diagnostics.
