Fix P2302: Mechanic’s solutions that WORKED

The P2302: Ignition Coil “A” Secondary Circuit code indicates a problem with the secondary circuit of ignition coil “A”. This coil is part of the engine’s ignition system, which is critical for igniting the fuel-air mixture in the combustion chamber. A fault in this circuit can lead to engine misfires, reduced power, and potentially more serious engine issues.

P2302 quick overview

Meaning	P2302: Ignition Coil “A” Secondary Circuit
Is it serious?	This code can be serious as it typically indicates a problem with the vehicle’s ignition system, which may lead to misfires and poor engine performance.
Possible causes	– Faulty ignition coil – Damaged or corroded coil connectors or wiring – Issues with the ignition coil’s control circuit – Faulty Powertrain Control Module (PCM) – Mechanical engine problems affecting ignition
How to diagnose?	Inspect Ignition Coil: Check the ignition coil for physical damage or signs of failure. Check Coil Connectors and Wiring: Look for damaged, corroded, or loose connectors and wiring. Test Coil Circuit: Use a multimeter to test the coil circuit for proper voltage and grounding. Evaluate PCM: Consider the possibility of a faulty PCM, especially if other diagnostic steps don’t reveal issues. Perform a Compression Test: A compression test can help rule out underlying mechanical issues.

How to fix P2302 – learn from mechanics

I looked into P2302 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Chrysler

Vehicle Information: 2006 Chrysler 300 2.7L

Issue + Repair History:

• Codes P2302 and PO301 present.
• Replaced injector, plug, and coil for cylinder 1.
• Lost pulse to injector #1, resolved with new computer.
• Still had code P2302 after computer replacement.

Computer Codes & Descriptions:

• P2302: Secondary circuit fault.
• PO301: Cylinder one misfire.

Suggestions to Fix Issue:

• Check other plugs on the same bank for carbon tracking.
• Swap coil and plug with another cylinder to see if misfire moves.
• Check for vacuum leak at the plenum or intake for cylinder 1.
• Look for potential wiring harness issues, especially around the valve covers.

Final Fix:

• Replaced with OEM coil, resolving code P2303.
• Installed new injector pigtail, which fixed the PO301 code.

Case #2: Dodge

Vehicle Information: 2006 Dodge Grand Caravan SE 3.3L

Issue + Repair History:

• Rough idle and code P2302.
• Weak spark observed on cylinders 3 & 4.
• Replaced spark plugs, wires, and coil pack without resolving the issue.
• Compression and oil pressure tested normal.

Computer Codes & Descriptions:

• P2302: Ignition coil secondary circuit #1 insufficient ionization.

Other Test Results:

• Weak spark in cylinders 3 & 4.
• Compression: 140-150 psi on all cylinders.
• Oil pressure: 50 psi at idle.
• 13.5 volts on dark blue/green coil pack wire.

Suggestions to Fix Issue:

• Unplug coil connector and test each terminal with a test light while cranking.
• Load test #1 coil driver circuit from the PCM to the coil pack.
• Check for physical damage or oil soaking on wiring to the coil.
• Verify the type of new coil used (OEM vs. aftermarket).

Final Fix:

• Replaced the Electronic Control Module (ECM) after finding one of the wires stayed lit (not blinking) during a test. This resolved the issue.

Case #3: Chrysler

Vehicle Information: 2003 Chrysler PT Cruiser GT 2.4L

Issue + Repair History:

• Initially had a misfire with codes P0303 and P2305.
• Replaced plugs, ignition wires, and coil pack assembly.
• Vehicle ran well until it warmed up, then experienced the same issues.
• Replaced coil again, but problem recurred after 15 miles of driving.

Computer Codes & Descriptions:

• P2305: Ignition coil #2 secondary circuit insufficient ionization.
• P2302: Ignition coil #1 secondary circuit insufficient ionization.

Other Test Results:

• Voltage at idle: 14.23 volts.

Suggestions to Fix Issue:

• Check for head gasket leaks and injector harness issues.
• Use an OEM coil from Chrysler instead of an aftermarket one.
• Inspect the fuel rail for dirt and potential blockage.
• Consider timing belt synchronization and cam/crank sensor function.
• Possible PCM issue or the need for a reflash.

Final Fix:

• Replaced the aftermarket ignition coil with an OEM coil from Chrysler, which resolved the issue. Vehicle ran well past the previously problematic time.

Case #4: Dodge

Vehicle Information: 2004 Dodge Grand Caravan SE 3.3L

Issue + Repair History:

• Misfire present with codes P0303 and P2305 initially.
• Replaced plugs, wires, coil pack, and crank sensor.
• After road test, codes P2302 and P2305 recurred.
• Replaced the coil again, but the problem persisted.

Computer Codes & Descriptions:

• P2308: Ignition coil #3 secondary circuit – insufficient ionization.

Other Test Results:

• Coil control for cylinders 5&2 and 1&4 were pulsing; 3&6 control was not.

Suggestions to Fix Issue:

• Check crank sensor or flywheel hub for sync signal issues.
• Scope oxygen sensors for proper functionality.
• Consider possibility of a faulty coil installed by the customer.
• Check wiring all the way to the PCM’s pin connector.
• Test secondary coil resistance to detect if it’s open.
• Examine the possibility of a faulty PCM driver.

Final Fix:

• Replaced both the ignition coil and PCM. Aftermarket coil was found to be shorting the new PCM. After replacing both, the vehicle was fixed.

Case #5: Jeep

Vehicle Information: 2018 Jeep Wrangler JK Rubicon 3.6L

Issue + Repair History:

• Recurring misfire on cylinder one.
• Initially replaced spark plug, misfire ceased for about 3 months, then returned.
• Replaced number 1 spark plug again, issue resolved temporarily.
• Replaced all 3 plugs on bank one and swapped coils between cylinders one and five, but misfire returned.
• Owner considered trading in the vehicle instead of internal repairs.

Computer Codes & Descriptions:

• P2302: Secondary ignition.
• P0301: Misfire on cylinder one.

Suggestions to Fix Issue:

• Test for consistent spark with an ST-125.
• Conduct compression and leak-down tests.
• Check for head gasket leaks and injector harness issues.
• Inspect cam lifters and rockers for mechanical problems.
• Consider valve guide issues.
• Review possible PCM failure as a primary cause.

Final Fix:

• The problem was resolved with a new PCM installation and programming, confirmed by another service provider. After the fix, the Jeep was traded in for a new Tundra.

Advice	Diagnostic Step
Check Ignition Coil	Inspect the ignition coil for signs of damage or failure. Replace with an OEM part if necessary.
Verify Coil Connections	Ensure wiring and connections to the coil are secure and not damaged. Check power supply and ground connections.
Inspect PCM (Powertrain Control Module)	Evaluate the PCM for faults, considering replacement if other diagnostics indicate a PCM issue.
Test Spark Plugs and Wires	Check spark plugs and wires for damage or wear. Replace if necessary.
Review Wiring Harness	Examine the wiring harness for damage, wear, or corrosion that might impact ignition system performance.
Load Test Coil Drivers	Perform a load test on coil drivers to ensure they are functioning correctly.
Check for Mechanical Issues	Investigate potential mechanical issues that could cause misfires, such as valve or camshaft problems.
Examine Cam and Crank Sensors	Test the camshaft and crankshaft sensors for proper operation.
Check for Software Updates	Verify if there are any available software updates for the vehicle’s ECM/PCM.
Conduct Compression Test	Perform a compression test to rule out internal engine issues.