The P0350 code means the engine control module has detected a general electrical malfunction in the ignition-coil primary or secondary circuit.
Unlike P0351 through P0362, P0350 doesn’t identify one particular ignition coil. It may indicate a problem affecting the entire ignition system, including a missing shared power supply, failed ignition relay, damaged wiring, poor ground, ignition-module fault or PCM coil-driver problem.
P0350 is not the same as a general engine misfire. A misfire code reports failed combustion. P0350 reports an electrical problem inside the system responsible for creating spark.
Before replacing every coil under the hood, test the shared circuits. Buying a complete coil set is certainly faster than understanding a wiring diagram, but speed and accuracy remain tragically unrelated.
P0350 Quick Reference
| Item | Information |
|---|---|
| OBD-II code | P0350 |
| Official description | Ignition Coil Primary/Secondary Circuit Malfunction |
| System | Ignition-coil control |
| Code type | Generic powertrain code |
| Primary fault | General coil-circuit electrical malfunction |
| Severity | High |
| Safe to drive? | Only for a short distance if the engine runs normally |
| Common causes | Missing coil power, failed relay, damaged wiring, shorted coil or PCM driver fault |
| Typical repair range | Approximately $75–$2,500+, depending on the cause |
What Does the P0350 Code Mean?
P0350 stands for:
Ignition Coil Primary/Secondary Circuit Malfunction
The ignition system converts low battery voltage into the much higher voltage required to create a spark across each spark plug gap.
Depending on the vehicle, the ignition system may use:
- One conventional ignition coil
- A distributor-mounted coil
- A waste-spark coil pack
- Several coil packs
- Coil-near-plug ignition
- Individual coil-on-plug units
- An external ignition-control module
- Smart coils containing internal ignition electronics
The ECM or PCM controls ignition timing by commanding the coil, ignition-control module or integrated coil driver.
What Is the Primary Ignition Circuit?
The primary ignition circuit is the low-voltage side of the ignition coil.
It may include:
- Battery
- Ignition fuse
- Main or ignition relay
- Coil power supply
- Primary coil winding
- Ignition-control module
- PCM coil driver
- Control wire
- Electrical connectors
- Engine and module grounds
The PCM or ignition module controls current through the primary winding. When that current is switched off, the magnetic field inside the coil collapses rapidly.
That collapse induces high voltage in the secondary winding.
A primary circuit problem may include:
- Missing battery voltage
- Open primary winding
- Shorted winding
- Broken control wire
- Failed relay
- Poor connector contact
- Failed ignition module
- Damaged PCM coil driver
What Is the Secondary Ignition Circuit?
The secondary ignition circuit is the high-voltage side that delivers spark to the combustion chamber.
Depending on the system, it may include:
- Secondary coil winding
- Coil boot
- Spark-plug wire
- Distributor cap and rotor
- Spark plug
- Ground path through the engine
Secondary ignition voltage may reach tens of thousands of volts.
Possible secondary problems include:
- Open secondary winding
- Cracked coil housing
- Carbon tracking
- Damaged coil boot
- Excessive spark-plug gap
- Open plug wire
- Corroded distributor terminal
- Spark leaking to ground
- Fouled or damaged spark plug
The PCM doesn’t always monitor secondary voltage directly. On many vehicles, it infers secondary operation by monitoring primary current, coil-driver feedback or changes in crankshaft speed.
This distinction matters. P0350 may mention the primary and secondary circuit even though the computer primarily detected an abnormality on the low-voltage control side.
How Serious Is the P0350 Code?
P0350 should be considered a high-severity code.
The engine may continue running if the fault is intermittent or affects only part of the ignition system. A complete loss of shared coil power can cause the engine to stall or prevent it from starting.
Continued operation with an active ignition fault may cause:
- Engine stalling
- No-start condition
- Severe misfires
- Loss of power
- Unsafe acceleration
- Unburned fuel entering the exhaust
- Catalytic-converter overheating
- Catalytic-converter failure
- Damage to the PCM coil driver
- Damage to additional ignition components
Stop driving if:
- The Check Engine Light flashes
- The engine shakes violently
- The engine stalls
- Acceleration becomes unsafe
- A strong raw-fuel odor develops
- The exhaust or catalytic converter glows
- The vehicle repeatedly fails to restart
- Multiple cylinders stop firing
A flashing Check Engine Light usually indicates a catalyst-damaging misfire. Reducing load and continuing to drive is not a repair strategy. It’s just a slower way to purchase a catalytic converter.
Common P0350 Symptoms
Possible symptoms include:
- Illuminated Check Engine Light
- Flashing Check Engine Light
- Engine cranks but won’t start
- Engine starts and immediately stalls
- Rough idle
- Severe engine shaking
- Hesitation
- Jerking during acceleration
- Reduced engine power
- Poor throttle response
- Intermittent stalling
- Misfire under load
- Poor fuel economy
- Raw-fuel odor
- Reduced-power mode
- Several cylinder-misfire codes
- Multiple ignition-coil circuit codes
- No spark from several or all cylinders
The symptoms depend on which part of the ignition system failed.
A missing shared coil-power supply may disable every cylinder. A damaged coil driver may affect only one circuit while still causing P0350 on certain vehicles.
Common Causes of the P0350 Code
Possible causes include:
- Blown ignition-coil fuse
- Failed ignition or main relay
- Missing shared coil power supply
- Open coil power-feed wire
- Excessive resistance in the shared power circuit
- Loose ignition-coil connector
- Corroded connector terminals
- Oil or water inside a coil connector
- Harness damage near the engine
- Wiring melted against an exhaust component
- Coil-control wire shorted to ground
- Coil-control wire shorted to voltage
- Open coil-control circuit
- Failed ignition coil
- Internally shorted ignition coil
- Open primary coil winding
- Failed ignition-control module
- Poor engine ground
- Poor PCM ground
- Low battery voltage
- Charging-system overvoltage
- Failed crankshaft or camshaft position input
- Damaged PCM connector
- Failed PCM coil driver
- Incorrect replacement ignition coil
- Aftermarket ignition-system wiring
- Remote-start or alarm installation damage
- Water intrusion after engine cleaning
- Rodent-damaged wiring
- PCM software or calibration issue
A failed crankshaft or camshaft sensor may prevent the PCM from commanding the coils because the computer cannot determine engine position. However, those faults usually store their own sensor codes and should be diagnosed separately.
P0350 vs P0351 Through P0362
P0350 identifies a general ignition-coil circuit malfunction. P0351 through P0362 identify individual coil circuits.
| Code | Circuit |
| P0350 | General ignition-coil primary/secondary circuit malfunction |
| P0351 | Ignition Coil A primary/secondary circuit |
| P0352 | Ignition Coil B primary/secondary circuit |
| P0353 | Ignition Coil C primary/secondary circuit |
| P0354 | Ignition Coil D primary/secondary circuit |
| P0355 | Ignition Coil E primary/secondary circuit |
| P0356 | Ignition Coil F primary/secondary circuit |
| P0357 | Ignition Coil G primary/secondary circuit |
| P0358 | Ignition Coil H primary/secondary circuit |
| P0359 | Ignition Coil I primary/secondary circuit |
| P0360 | Ignition Coil J primary/secondary circuit |
| P0361 | Ignition Coil K primary/secondary circuit |
| P0362 | Ignition Coil L primary/secondary circuit |
Coil letters usually correspond to cylinder order, but manufacturers may assign them differently.
Do not assume Coil A always means cylinder one without consulting vehicle-specific service information.
If P0350 appears with several individual coil codes, inspect circuits shared by those coils before replacing multiple components.
P0350 vs P0300
P0350 and P0300 may appear together, but they report different faults.
P0350 means the ECM detected an electrical malfunction in the ignition-coil system.
P0300 means the ECM detected random or multiple-cylinder combustion misfires.
A P0300 may be caused by:
- Ignition problems
- Fuel-delivery problems
- Vacuum leaks
- Low compression
- Valve-timing problems
- Sensor faults
P0350 narrows the investigation toward the ignition system.
Use the P0300 random or multiple-cylinder misfire guide when combustion failures are present but a specific electrical coil fault hasn’t been confirmed.
For broader symptom diagnosis, visit the engine misfire symptoms, causes and diagnosis guide.
P0350 vs Bad Ignition-Coil Symptoms
P0350 shouldn’t be confused with a broad diagnosis of a weak ignition coil.
A weak coil may cause:
- Misfire under load
- Rough idle
- Hesitation
- Poor acceleration
- Hard starting
- Reduced fuel economy
However, a weak coil doesn’t always store P0350.
P0350 is set when the PCM detects an electrical circuit problem. The fault may be outside the coil itself, including the fuse, relay, shared power supply, control wire or PCM driver.
For general component symptoms, use the existing bad ignition-coil symptoms guide. This P0350 guide remains focused on the trouble code and its shared electrical circuits.
How the Ignition-Coil Circuit Works
A typical coil-on-plug ignition cycle works like this:
- The ignition relay supplies battery voltage to the coil.
- The PCM receives crankshaft and camshaft position information.
- The PCM calculates ignition timing and coil dwell.
- The PCM or internal coil electronics completes the primary circuit.
- Current builds through the primary winding.
- The control circuit switches off.
- The coil’s magnetic field collapses.
- High voltage is induced in the secondary winding.
- Voltage jumps across the spark-plug gap.
- Combustion occurs.
A fault anywhere in the power, control, coil or secondary path may interfere with spark production.
Some smart coils contain their own power transistor. The PCM sends a low-current command instead of directly controlling primary coil current.
Testing procedures differ significantly between conventional coils, waste-spark coil packs and smart coil-on-plug systems. Use the correct wiring diagram and specifications.
How to Diagnose the P0350 Code
1. Verify the Code Definition
Connect a capable scan tool and confirm that P0350 is identified as:
Ignition Coil Primary/Secondary Circuit Malfunction
Some manufacturers may not use P0350, or they may apply additional platform-specific diagnostic logic.
Record:
- Stored codes
- Pending codes
- Permanent codes
- Freeze-frame data
- Misfire counters
- Battery voltage
- Engine speed
- Cranking RPM
- Camshaft and crankshaft synchronization
Do not clear the code before saving the diagnostic information.
2. Check for Related Trouble Codes
Look for:
- P0300 random misfire
- P0301 through P0312 cylinder misfires
- P0351 through P0362 individual coil circuits
- Crankshaft-position sensor codes
- Camshaft-position sensor codes
- System-voltage codes
- Communication codes
- Immobilizer or security codes
Related codes help determine whether P0350 represents:
- One coil circuit
- Several coil circuits
- A shared power failure
- A missing engine-speed input
- Low system voltage
- A PCM communication problem
If several coil-circuit codes appeared simultaneously, shared power, relay, fuse and ground faults become more likely than several coils failing at the exact same moment.
Components do occasionally coordinate their retirement, but wiring remains the more believable suspect.
3. Determine Whether Spark Is Missing
If the engine cranks but won’t start, verify whether spark is present using an approved spark tester.
Before cranking:
- Secure the vehicle
- Keep loose clothing away from moving components
- Disable fuel delivery when required
- Follow manufacturer procedures
- Keep hands away from coil outputs
- Avoid testing near fuel vapor
Do not hold a coil boot, plug wire or spark plug with your hand while cranking. Secondary ignition voltage can exceed 20,000 volts and may be dangerous.
If every cylinder lacks spark, inspect shared ignition power, PCM inputs and system control.
If only one cylinder lacks spark, look for an individual coil code and test that circuit.
4. Check Battery Voltage
Measure battery voltage:
- With the engine off
- During cranking
- At idle
- With electrical loads operating
Low cranking voltage may prevent the PCM, ignition module or smart coils from operating correctly.
Inspect:
- Battery terminals
- Positive cables
- Engine grounds
- Chassis grounds
- PCM grounds
- Main fuse-box connections
If the engine cranks slowly, address the battery or cable problem before diagnosing low-voltage ignition operation.
5. Inspect the Ignition Fuses
Locate every fuse related to:
- Ignition coils
- Engine control
- PCM or ECM
- Main relay
- Ignition relay
- Fuel injection
- Engine management
Do more than look at the fuse element. Test for voltage on both sides of the fuse with the circuit powered.
A fuse may appear intact while its terminal has poor contact inside the fuse box.
If a replacement fuse blows immediately, don’t install a larger fuse. Locate the shorted coil, wire or module responsible for the excessive current.
A bigger fuse is not an electrical repair. It’s an arson starter kit.
6. Test the Ignition Relay
If the ignition coils share a relay, verify:
- Relay power supply
- Relay control
- Relay ground
- Switched output
- Voltage drop across the contacts
- Terminal tension in the relay socket
A relay may click but still have burned contacts that cannot carry the required current.
Swap the relay only when the comparison relay has the same part number and terminal configuration.
7. Inspect the Ignition-Coil Connectors
Disconnect the coil connectors and inspect them for:
- Bent terminals
- Recessed pins
- Spread female terminals
- Broken locking tabs
- Corrosion
- Water intrusion
- Oil contamination
- Melted plastic
- Heat discoloration
- Improper previous repairs
Oil inside a spark-plug well can damage coil boots and connectors. Repair the valve-cover or tube-seal leak instead of repeatedly cleaning the evidence.
Perform terminal-drag testing when appropriate. A connector may look normal while failing to grip the coil terminal.
8. Inspect the Wiring Harness
Follow the ignition harness where practical.
Pay close attention to areas near:
- Valve covers
- Exhaust manifolds
- Cylinder heads
- Intake-manifold brackets
- Engine mounts
- Harness retainers
- Fuse boxes
- PCM connectors
- Previous engine repairs
Look for:
- Melted insulation
- Chafed wires
- Pinched harness sections
- Broken conductors
- Poor splices
- Missing retainers
- Rodent damage
- Aftermarket wiring
- Harness contact with sharp metal
Move the harness while monitoring coil power or control signals. If the voltage or waveform changes, suspect an intermittent internal break or loose terminal.
9. Test the Shared Coil Power Supply
Turn the ignition on and measure voltage at the coil power terminal.
Many coil-on-plug systems supply battery voltage to every coil through one fuse and relay. Some systems divide the coils into multiple power groups.
Compare measured voltage with battery voltage.
If power is missing:
- Check the fuse.
- Test the relay.
- Inspect the power-feed wire.
- Check shared splices.
- Perform a voltage-drop test.
- Disconnect coils to determine whether one unit is pulling down the circuit.
If voltage is present with the coils disconnected but collapses under load, suspect excessive resistance or a shorted coil.
10. Perform Voltage-Drop Testing
Voltage-drop testing is more useful than basic continuity testing when the circuit carries current.
Test voltage drop across:
- Ignition relay contacts
- Coil power wiring
- Connectors
- Ground circuits
- Fuse-box terminals
- Harness splices
A wire may show continuity with a multimeter while failing to deliver enough current to operate several coils.
Compare measurements with manufacturer specifications.
11. Check Coil Grounds
Some ignition coils use a dedicated ground terminal. Others ground through the ignition module or PCM-controlled driver.
Inspect and test:
- Coil ground wires
- Engine grounds
- Cylinder-head grounds
- PCM grounds
- Ignition-module ground
- Ground splices
Use voltage-drop testing while cranking or running the engine.
A loose engine ground may cause several ignition coils and sensors to fail simultaneously.
12. Verify Crankshaft and Camshaft Signals
The PCM normally requires valid crankshaft and camshaft information before commanding spark.
Monitor scan data for:
- Engine RPM while cranking
- Crankshaft synchronization
- Camshaft synchronization
- Engine-position status
- Security authorization
If the scan tool displays zero RPM during cranking, investigate the crankshaft-position circuit.
If camshaft or crankshaft signals disappear, diagnose their codes before condemning the coil system.
A PCM that doesn’t know the engine is rotating has little reason to fire the coils.
13. Test the Coil-Control Signal
Use the manufacturer’s wiring diagram to identify the coil-control terminal.
Testing may require:
- LED test light
- Logic probe
- Lab scope
- Current probe
- Manufacturer-specific breakout leads
Do not use a conventional incandescent test light on a PCM coil-driver circuit unless the manufacturer explicitly approves it. Excessive current can damage the module.
Observe the control signal during cranking or engine operation.
If every coil has power but none receives a control signal, investigate:
- Crankshaft input
- Camshaft input
- Immobilizer authorization
- PCM power and ground
- Ignition module
- PCM operation
14. Inspect the Primary Waveform
An oscilloscope can reveal how the primary circuit charges and discharges.
Possible waveform information includes:
- Dwell time
- Primary current rise
- Current limiting
- Driver switching
- Coil saturation
- Primary voltage spike
- Burn time
- Oscillation after spark
A current probe can show the primary current ramp without opening the circuit.
Abnormal patterns may indicate:
- Shorted primary winding
- Open coil
- Excessive circuit resistance
- Weak power supply
- Driver not switching
- Coil saturation problem
- Faulty smart-coil electronics
Compare the pattern with a known-good coil on the same engine whenever possible.
15. Test Individual Ignition Coils
Test each coil according to its design.
Possible methods include:
- Scan-tool cylinder disable
- Coil swap test
- Approved spark tester
- Primary-current waveform
- Secondary waveform
- Manufacturer resistance test
- Known-good substitution
Resistance testing isn’t conclusive for many modern smart coils. Their internal electronics may prevent meaningful winding measurements at the external terminals.
Do not pierce coil insulation or force oversized probes into connector terminals.
If one shorted coil pulls down the shared power circuit, disconnect coils one at a time while monitoring circuit voltage or fuse behavior. Follow the service procedure and avoid reconnecting coils with the ignition on unless permitted.
16. Inspect the Secondary Ignition Components
Inspect:
- Spark plugs
- Coil boots
- Spark-plug wires
- Distributor cap
- Rotor
- Coil towers
- Plug wells
Look for:
- Excessive spark-plug gap
- Carbon tracking
- Cracked porcelain
- Oil contamination
- Water intrusion
- Burned terminals
- Damaged insulation
- Corrosion
- Open plug wires
High secondary resistance forces the coil to generate greater voltage. This can eventually damage the coil insulation or driver circuit.
For component-specific diagnosis, My Pro Street has existing guides covering:
- Subaru Forester ignition-coil testing
- 420A coil-pack testing
- VQ35 ignition-coil testing
- Lexus IS300 ignition-coil testing
Use the specifications for the actual vehicle rather than borrowing resistance values from an unrelated coil design.
17. Test the Ignition-Control Module
Some vehicles use a separate ignition-control module between the PCM and ignition coils.
Verify:
- Module power
- Module ground
- PCM trigger input
- Coil-control output
- Bypass or timing-control circuit
- Module connector condition
- Heat-related failure
An ignition module may fail when hot and resume operation after cooling.
Test it using the manufacturer’s procedure. Resistance measurements alone may not identify a module that fails dynamically.
18. Test the PCM Driver Last
A shorted ignition coil or control wire can damage the PCM’s internal driver transistor.
Suspect a PCM driver only after confirming:
- Proper PCM power
- Reliable PCM ground
- Valid crankshaft signal
- Valid camshaft signal
- Security authorization
- Correct coil power
- Good control-wire continuity
- No short to ground
- No short to voltage
- Correct ignition coil
- No external ignition-module fault
If one PCM control terminal never switches while equivalent circuits work normally, driver failure becomes more likely.
Before installing a replacement PCM, locate and repair the condition that damaged the original driver. Otherwise, the replacement module may enjoy an extremely brief career.
PCM replacement may require:
- Programming
- Immobilizer setup
- Key relearning
- Crankshaft variation relearn
- Vehicle-specific configuration
Common P0350 Diagnostic Mistakes
Avoid these common mistakes:
- Replacing every ignition coil at once
- Treating P0350 as a cylinder-specific code
- Ignoring the shared coil-power circuit
- Looking at a fuse without testing both sides
- Assuming a clicking relay is good
- Using only a continuity test
- Ignoring voltage drop under load
- Replacing spark plugs for a missing control signal
- Overlooking engine and PCM grounds
- Ignoring crankshaft-position data
- Using an incandescent test light on a PCM driver
- Applying unrelated resistance specifications
- Replacing the PCM without testing for a shorted coil
- Continuing to drive with a flashing Check Engine Light
P0350 identifies an electrical ignition-system problem. Diagnose the power, ground and control circuits before treating it like a general maintenance reminder.
How Do You Fix the P0350 Code?
The correct repair depends on the confirmed fault.
Possible repairs include:
- Replacing a blown ignition fuse
- Repairing the short that caused the fuse to fail
- Replacing a failed ignition relay
- Repairing the shared coil-power circuit
- Repairing a damaged ground
- Replacing a damaged coil connector
- Repairing corroded terminals
- Repairing chafed or melted wiring
- Replacing a failed ignition coil
- Replacing damaged coil boots
- Replacing worn spark plugs
- Replacing damaged spark-plug wires
- Replacing a failed ignition-control module
- Repairing PCM connector terminals
- Updating PCM software
- Replacing and programming the PCM when driver failure is confirmed
After repairs:
- Clear stored trouble codes.
- Start the engine from cold.
- Monitor misfire counters.
- Verify stable coil power.
- Confirm every coil receives a control signal.
- Road-test under the conditions shown in freeze-frame data.
- Rescan for pending codes.
- Verify that P0350 and related misfire codes don’t return.
P0350 Repair Costs
Repair costs vary by vehicle and failure.
| Repair | Estimated cost |
| Diagnostic inspection | $100–$300 |
| Replace fuse or relay | $50–$250 |
| Repair coil connector | $100–$350 |
| Repair ignition wiring | $100–$800 |
| Replace one ignition coil | $100–$450 |
| Replace spark plugs | $100–$500 |
| Replace coil pack | $150–$600 |
| Replace ignition-control module | $250–$900 |
| Repair engine wiring harness | $500–$2,500+ |
| PCM software update | $100–$300 |
| Replace and program PCM | $800–$2,500+ |
These are general estimates. Access, labor rates, coil design and diagnostic time can change the final cost significantly.
Can You Drive With a P0350 Code?
Driving with P0350 isn’t recommended when the engine is actively misfiring.
A short drive to a repair facility may be possible if:
- The engine runs smoothly
- The Check Engine Light remains steady
- No raw-fuel odor is present
- The engine doesn’t stall
- Acceleration remains normal
Stop driving if:
- The Check Engine Light flashes
- The engine shakes
- Power drops substantially
- The vehicle stalls
- Raw fuel can be smelled
- The catalytic converter overheats
- The engine repeatedly fails to restart
Unburned fuel can overheat the catalytic converter quickly. A tow bill is frequently cheaper than a converter, especially when the converter arrives with several oxygen sensors and an emotional-support heat shield.
P0350 Frequently Asked Questions
Does P0350 mean all ignition coils are bad?
No. P0350 identifies a general coil-circuit malfunction. The problem may be a shared fuse, relay, power wire, ground, ignition module or PCM driver.
Which ignition coil does P0350 identify?
P0350 doesn’t identify a specific coil. Individual coil circuits are normally represented by P0351 through P0362.
Can a bad ignition coil cause P0350?
Yes. A coil with an open or shorted primary circuit can trigger P0350. A shorted coil may also pull down a shared power circuit or damage the PCM driver.
Can a blown fuse cause P0350?
Yes. A blown ignition-coil fuse may remove power from several or all coils. Find the cause of the blown fuse before replacing it.
Can a bad relay cause P0350?
Yes. Burned relay contacts may interrupt coil power or create excessive voltage drop.
Can a weak battery cause P0350?
Low battery voltage during cranking can interfere with PCM and ignition-system operation. Test battery voltage, terminals and grounds.
Can a crankshaft sensor cause P0350?
Indirectly. If the PCM loses the crankshaft-position signal, it may stop commanding the coils. Crankshaft sensor codes or zero cranking RPM usually accompany this condition.
Can worn spark plugs cause P0350?
Excessive plug gap increases secondary ignition demand and may stress the coil, but worn plugs more commonly cause misfire codes than a direct P0350 circuit fault.
Can P0350 cause a no-start condition?
Yes. If the fault disables shared coil power or coil control, the engine may crank normally without producing spark.
Is P0350 the same as P0300?
No. P0350 identifies an ignition-coil electrical fault. P0300 identifies random or multiple-cylinder combustion misfires.
Can I test ignition coils with a multimeter?
Sometimes. Older coils and certain coil packs have manufacturer resistance specifications. Many modern smart coils require waveform, power, ground and trigger-signal testing instead.
Can a PCM cause P0350?
Yes, but PCM failure is less common than fuse, relay, connector, wiring or ignition-coil problems. Test the external circuit first.
Final Thoughts
P0350 means the PCM has detected a general malfunction in the ignition-coil primary or secondary circuit.
Begin by recording every trouble code and reviewing freeze-frame information. If multiple coil codes or misfires appeared together, inspect shared ignition power, fuses, relays and grounds before replacing individual coils.
Verify battery voltage, test both sides of each ignition fuse and measure voltage at the coil connectors. Perform voltage-drop testing under load, confirm crankshaft and camshaft synchronization and inspect coil-control signals with appropriate equipment.
Use an oscilloscope and current probe when possible. A primary current ramp can reveal a shorted coil, excessive resistance, missing driver command or weak power supply considerably faster than a pile of replacement parts.
Test the PCM last—and repair any shorted coil or wiring before connecting another module.
For additional diagnostic coverage, visit the complete P-series OBD-II code guide, browse the OBDII Doctor archive or compare the symptoms with the engine misfire diagnosis guide.
P0350 doesn’t tell you which coil failed because that would be convenient. Instead, it gives you an electrical system and wishes you the very best.
