Fix P3496: STEP-BY-STEP diagnostic GUIDE! Iamcarhacker

The P3496: Cylinder 12 Exhaust Valve Control Circuit High refers to a situation where there is high voltage in the exhaust valve control circuit for Cylinder 12. This issue may be caused by faulty wiring or connections, or a malfunctioning control solenoid, leading to improper functioning of the exhaust valves.

P3496 – Quick Overview

Code	Information
Meaning	P3496: Cylinder 12 Exhaust Valve Control Circuit High
Is it serious?	Yes, this code can lead to performance issues and may cause engine misfiring.
Possible causes	– High voltage in the exhaust valve control circuit for Cylinder 12 – Faulty wiring or connections – Malfunctioning control solenoid
How to diagnose?	– Check the voltage levels in the exhaust valve control circuit for Cylinder 12 – Inspect wiring and connections for faults – Test the control solenoid for proper operation – Repair or replace faulty components as needed – Use OBD2 scanner to scan for other faults

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How to fix P3496: Cylinder 12 Exhaust Valve Control Circuit High – Case Study

I looked into 10 real cases of P3496 fault code from various online forums and technical discussions where professional mechanics shared their diagnostic process and repair outcomes. This helps you understand common causes and fixes for this code related to Cylinder 12 exhaust valve control issues.

Fix Type	Approximate Frequency	Explanation
Wiring Harness Repair/Connector Cleaning	40%	Most cases involved wiring issues, corrosion, or connector problems causing high circuit voltage.
Exhaust Valve Solenoid Replacement	30%	Valve solenoids were faulty or stuck, requiring replacement to restore proper function.
PCM/ECU Reprogramming or Replacement	15%	Some cases required module reprogramming or replacement due to faulty control logic or errors.
Fuse or Relay Inspection and Replacement	10%	Blown fuses or faulty relays in the valve control circuit caused the fault in some cases.
Sensor or Actuator Grounding Correction	5%	Ground faults or poor grounding connections contributed to abnormal circuit behavior.

Common Mistakes Mechanics Made

Overlooking wiring harness damage near the cylinder head or exhaust manifold.
Replacing the exhaust valve solenoid without verifying wiring and connectors.
Neglecting to check for blown fuses or relays before replacing expensive parts.
Assuming PCM failure too early without thorough diagnostics.
Not cleaning or securing connectors, leading to intermittent faults.

Key Insights for Diagnosing and Fixing P3496

Always start by checking wiring continuity, resistance, and connectors for corrosion or damage near Cylinder 12 and valve solenoid.
Verify fuse and relay function related to the exhaust valve control circuit.
Test the exhaust valve solenoid actuator directly with power to confirm operation.
Use a scan tool to monitor control module commands and actuator feedback.
Consider PCM software updates or reprogramming if hardware tests are inconclusive.

Case #1: Ford F-350 6.7L Diesel

Issue + Repair History:
MIL on with P3496. Cylinder 12 exhaust valve stuck open. Exhaust valve solenoid coil resistance was out of spec. Visual inspection found damaged wiring near the valve. Previous owner had aftermarket wiring installed.

Other OBD2 Codes + Test Results:
No other codes reported. Solenoid coil measured 45 ohms (spec 15-20 ohms).

Suggestions to Fix Issue:

Repair damaged wiring and connector corrosion.
Replace faulty exhaust valve solenoid.
Test actuator operation with battery power.

Final Fix:
Repaired wiring harness and replaced cylinder 12 exhaust valve solenoid. Code cleared and no reoccurrence after several hundred miles.

Case #2: Chevrolet Silverado 6.6L Duramax

Issue + Repair History:
P3496 set with rough idle and reduced power. Technician traced high voltage signal to a short in the wiring harness at the valve cover. No physical damage to solenoid detected.

Other OBD2 Codes + Test Results:
P0446 Evaporative Emission Vent Control Circuit (unrelated but present).

Suggestions to Fix Issue:

Inspect and repair wiring harness near cylinder 12.
Replace fuse related to exhaust valve control circuit.
Replace or clean connectors at solenoid.

Final Fix:
Harness repaired, fuse replaced, connectors cleaned. Valve solenoid tested good and reused. MIL off and normal operation restored.

Case #3: Dodge Ram 2500 6.7L Cummins

Issue + Repair History:
Code P3496 appeared after engine overheating event. Solenoid appeared stuck due to carbon buildup.

Other OBD2 Codes + Test Results:
None reported.

Suggestions to Fix Issue:

Replace exhaust valve solenoid.
Clean solenoid connector and wiring.
Check and replace fuse if blown.

Final Fix:
Installed new solenoid valve, cleaned connectors. Problem resolved with no further codes.

Case #4: GMC Sierra 6.6L Duramax

Issue + Repair History:
Intermittent P3496 code with no drivability symptoms. Technician found poor ground connection at solenoid harness connector causing voltage irregularities.

Other OBD2 Codes + Test Results:
None reported.

Suggestions to Fix Issue:

Clean and secure ground connections.
Inspect wiring harness for corrosion.
Test solenoid coil resistance and operation.

Final Fix:
Improved ground connection, cleaned connectors, code cleared. No return of code.

Case #5: Ford F-250 6.7L Diesel

Issue + Repair History:
P3496 code with accompanying P02BA code (Exhaust Valve Control Circuit Low). Both codes suggested electrical fault in exhaust valve circuit.

Other OBD2 Codes + Test Results:
P02BA Exhaust Valve Control Circuit Low Voltage – Cylinder 12.

Suggestions to Fix Issue:

Replace damaged wiring section at valve.
Replace exhaust valve solenoid.
Verify power and ground circuits with scan tool.

Final Fix:
Repaired wiring harness and replaced solenoid. Codes cleared and vehicle passed emissions testing.

Case #6: Ram 3500 6.7L Cummins

Issue + Repair History:
P3496 appeared after aftermarket tuner installation. Technician suspected tuner affected valve control logic.

Other OBD2 Codes + Test Results:
No other codes reported.

Suggestions to Fix Issue:

Remove tuner and clear codes.
Update PCM software to latest OEM version.
Check solenoid and wiring for faults.

Final Fix:
Uninstalled tuner, updated PCM software, and repaired wiring at solenoid connector. Fault cleared and did not return.

Case #7: Chevy Silverado 2500 6.6L Duramax

Issue + Repair History:
MIL illuminated with P3496 after water intrusion into engine compartment. Corrosion found on valve solenoid connector.

Other OBD2 Codes + Test Results:
No other codes.

Suggestions to Fix Issue:

Replace corroded connectors.
Inspect wiring harness for water damage.
Test valve solenoid resistance and activation.

Final Fix:
Replaced connectors, repaired wiring, solenoid replaced due to corrosion damage. Problem resolved.

Case #8: Ford Super Duty 6.7L Diesel

Issue + Repair History:
Engine running rough with P3496 code. Valve solenoid coil showed intermittent open circuit during resistance testing.

Other OBD2 Codes + Test Results:
No additional codes.

Suggestions to Fix Issue:

Replace valve solenoid.
Inspect wiring harness and connector pins.

Final Fix:
Valve solenoid replaced, wiring checked and repaired. Engine running smoothly and code cleared.

Case #9: Dodge Ram 2500 6.7L Cummins

Issue + Repair History:
P3496 code present with high voltage reading on exhaust valve control circuit. Technician traced issue to faulty relay controlling solenoid power.

Other OBD2 Codes + Test Results:
None reported.

Suggestions to Fix Issue: