Fix P0352: Mechanic’s solutions that WORKED

The P0352: Ignition Coil ‘B’ Primary/Secondary Circuit Malfunction code indicates an issue with the ‘B’ primary/secondary circuit of an ignition coil, which is crucial for generating the spark needed to ignite the air-fuel mixture in the engine. This malfunction can result in misfires, affecting the vehicle’s performance and efficiency.

P0352 quick overview

Meaning	P0352: Ignition Coil ‘B’ Primary/Secondary Circuit Malfunction
Is it serious?	This code is quite serious as it can lead to engine misfires, poor performance, and potentially cause damage to other components if left unaddressed.
Possible causes	– Faulty ignition coil for cylinder 2 – Damaged or corroded coil wiring or connectors – Faults in the primary circuit of the ignition system – Problems with the Engine Control Module (ECM)
How to diagnose?	Inspect Ignition Coil: Check the coil for any signs of damage or wear. Check Wiring and Connectors: Examine the wiring and connectors to the coil for damage or corrosion. Scope Primary Circuit: Use an oscilloscope to check the primary circuit waveform. Test Coil Operation: Perform tests to evaluate the functioning of the ignition coil. Evaluate ECM: Consider the possibility of an ECM malfunction affecting the ignition circuit.

How to fix P0352 – learn from mechanics

I looked into P0352 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: Toyota

Vehicle Information: 2006 Toyota RAV4 Limited 3.5L, Misfire, MIL Lamp on

Issue + Repair History:

• Intermittent P0352 code with low mileage.
• Initially suspected a pinched pigtail for coil #2; replaced pigtail but issue recurred after 50 miles.
• Conducted visual and circuit tests on wiring from coil to ECM for damage (such as from mice), but found none.
• Swapped coils and plugs, but the P0352 code persisted.
• Suspected ECM issue but sought further confirmation.

Other OBD2 Codes + Test Results:

• P0352 – Ignition coil #2 primary/secondary circuit
• Swap plug: same code
• Swap coil: same code
• Replace pigtail: same code

Suggestions to Fix Issue:

• Check IGT wires on all coils.
• Conduct compression test on all cylinders.
• Swap coil #2 to a different cylinder to see if the code changes.
• Consider replacing all ignition coils.
• If wiring is good and swapping coils doesn’t change the code, suspect an issue with the ECM.

Final Fix:

• After swapping injectors, checking compression, and scoping coils, the ECM was suspected to be the issue.
• Vehicle sent to Toyota; they swapped coil #2 and #6 and the code moved.
• One new coil installed by Toyota; suspected a possible software update not disclosed. Vehicle fixed at this time.

Case #2: Lexus

Vehicle Information: 2007 Lexus ES350 3.5L, Hesitation, Surge, Misfire

Issue + Repair History:

• Experienced a surge under load and hesitation with DTC P0352.
• Originally had misfire on all cylinders along with this code.
• Recent service included oil change and air filter replacement at a dealer.
• Air inlet boot was left loose and vacuum line connection to the actuator on the air inlet was broken during service.
• After correcting these issues, the car was fine for a while, but the code returned.

Computer Codes & Descriptions:

• P0352d: Ignition coil B primary/secondary circuit malfunction

Suggestions to Fix Issue:

• Check #2 coil and wiring near it.
• Swap the #2 coil with another cylinder to see if the misfire and code follow.
• Change all front coils and spark plugs, and prepare to change rear coils and plugs at 120k mileage.
• Use OEM or Denso coils and consider changing harness connectors as they tend to break (part#90980-11885).

Final Fix:

• The issue was resolved by replacing the no. 2 coil after swapping and noticing the misfire moved.
• All three coils on the bank were replaced.
• Advised the customer to replace the other bank coils and plugs at 120k mileage.
• Noted that the P0352 code is for the IGF signal to cylinder no. 2.

Case #3: Chevrolet

Vehicle Information: 2001 Chevrolet Silverado 1500 5.3L, Excessive Emissions, Misfire, Poor Fuel Economy, MIL Lamp on

Issue + Repair History:

• MIL on with codes P0300 and P0352.
• Misfire counters indicated misfires in cylinders 2 and 6, especially in cylinder 2.
• Swapping coils between cylinders 2 and 4 didn’t resolve the issue.
• Changing the affected spark plugs also did not correct the condition.

Computer Codes & Descriptions:

• P0300 – Random/Multiple Cylinder Misfire Detected
• P0352 – Ignition Coil B Primary/Secondary Circuit Malfunction

Suggestions to Fix Issue:

• Check fuel pressure regulator for leaks or issues.
• Inspect injector flow and resistance.
• Utilize a smoke machine to check for vacuum leaks.
• Measure Hz on affected coil connector with a DMM set to DC Hz.
• Consider possibility of compression issues, such as broken valve spring or rocker.
• Check for intake vacuum leak and injector resistance.
• Clean the injectors.
• Investigate possible wiring issue at the ignition module connector or a defective Powertrain Control Module.

Final Fix:

• The issue was diagnosed as a voltage drop in the coil harness on the right-hand bank in the ground loop.

Case #4: Dodge

Vehicle Information: 2002 Dodge Ram 1500 SLT 4.7L, Poor Idle Quality, Misfire

Issue + Repair History:

• Experiencing misfire and idle surge.
• Coil current ramp occasionally stayed high, indicating no ramp.
• Scoped cam and crank with no issues found.
• Valve cover on one bank removed to inspect for cam timing problems.
• Replaced PCM, ran new primary wire from PCM to coil, swapped coils, replaced ignition capacitor.

Computer Codes & Descriptions:

• P0352 – Ignition Coil #2

Other Test Results:

• Followed flow chart, replaced PCM, but the same problem persisted.
• Voltage drop across all PCM grounds measured at 0.02 volts.

Suggestions to Fix Issue:

• Check for cylinder misfire and update idle fluctuation flash from Chrysler.
• Investigate fuel trims and possible vacuum leak.
• Check for a spark plug that’s carbon-tracked.

Final Fix:

• The problem was found to be bad O-rings on three injectors.
• Replacing the O-rings resolved the issue, with no recurrence of the P0352 code after 100 miles of testing.
• The technician was unsure why the PCM flagged the P0352 code for this type of fault but suspected it might be related to a high firing voltage requirement due to the lean condition caused by the bad O-rings.

Case #5: Ford

Vehicle Information: 2002 Ford Taurus LX 3.0L, Misfire, MIL Lamp on

Issue + Repair History:

• Slight misfire at startup for a few seconds, then smooths out.
• Cylinders 3 and 4 showed very weak spark compared to others.
• Scoped primary circuit showed irregular wave patterns for cylinders #3 and #4.
• Wire from coil to ECM tested for resistance and continuity, found to be good.
• Replaced PCM, ran new primary wire from PCM to coil, swapped coils, replaced ignition capacitor.

Computer Codes & Descriptions:

• P0352: Ignition coil B through J primary/secondary circuit malfunction

Suggestions to Fix Issue:

• Check for coil driver circuit failure.
• Perform load test on wire from coil to ECM.
• Check for possible intermittent breakdown of PCM pin 52 circuit.
• Consider head gasket or valve issues, especially if losing coolant.
• Check primary signal right out of PCM; if weak, consider replacing PCM.

Final Fix:

• The problem was diagnosed to be the ECM’s coil driver for cylinders #3 and #4.
• After scoping the primary pattern directly from the ECM, it was clear the pattern was not good compared to other cylinders.
• Replacing the ECM resolved the issue.

Advice	Brief Description of Diagnostic Step
Check Coil and Wiring	Inspect the ignition coil and wiring for any faults or irregularities.
Scope Primary Circuit	Use an oscilloscope to analyze the primary circuit wave pattern.
Replace ECM if Necessary	Consider replacing the Engine Control Module if diagnostics suggest a failure.
Check for Vacuum Leaks	Investigate potential vacuum leaks that could impact engine performance.
Inspect Fuel System Components	Check fuel injectors, fuel pressure regulator, and related components.
Verify Coil Pack Installation	Ensure that any replaced coil packs are installed correctly and functioning.
Load Test Relevant Wires	Perform a load test on wires related to the ignition system to check for voltage drop.
Investigate PCM Wiring and Connections	Examine the wiring and connections between the ignition coil and PCM for issues.
Consider Related Vehicle History	Take into account any recent repairs or replacements that could influence the issue.
Conduct Compression Tests	Perform a compression test to rule out mechanical issues such as valve or gasket problems.