Faulty ignition coil or spark plug voltage detection circuit wiring (open, short, or high resistance); Worn or fouled spark plugs in the rear bank preventing proper ionization signal; Defective ignition coil on one or more rear bank cylinders; Damaged or corroded connector at the ignition coil or PCM; PCM internal fault affecting the voltage detection circuit; Aftermarket or incorrect spark plugs that do not produce the expected ionization signal

DTC codes / Honda codes / P1317

P1317 · HondaSpark Plug Voltage Detection Circuit Malfunction Rear Bank

Q: What does code P1317 mean?

Spark Plug Voltage Detection Circuit Malfunction Rear Bank. P1317 on Honda vehicles indicates that the powertrain control module (PCM) has detected an abnormal signal from the spark plug voltage detection circuit for the rear bank of cylinders. The circuit monitors ionization voltage across the spark plug gap to confirm combustion quality, and this code sets when the returned voltage falls outside the expected range during engine operation.

P1317 on Honda vehicles indicates that the powertrain control module (PCM) has detected an abnormal signal from the spark plug voltage detection circuit for the rear bank of cylinders. The circuit monitors ionization voltage across the spark plug gap to confirm combustion quality, and this code sets when the returned voltage falls outside the expected range during engine operation.

SystemPowertrain

Code typeHonda specific

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Intermittent misfire or rough running, especially under load or during acceleration
Slight hesitation or stumble when the engine is cold
Reduced fuel economy due to incomplete combustion
In rare cases, a flashing check engine light if the misfire becomes severe

Common causes, most likely first

Faulty ignition coil or spark plug voltage detection circuit wiring (open, short, or high resistance)
Worn or fouled spark plugs in the rear bank preventing proper ionization signal
Defective ignition coil on one or more rear bank cylinders
Damaged or corroded connector at the ignition coil or PCM
PCM internal fault affecting the voltage detection circuit
Aftermarket or incorrect spark plugs that do not produce the expected ionization signal

How to diagnose and fix it

Inspect the rear bank spark plugs for wear, fouling, or incorrect gap and replace if necessary
Check the ignition coil connectors and wiring for the rear bank for corrosion, looseness, or damage
Perform a resistance test on the spark plug voltage detection circuit wiring between the coil and PCM
Swap ignition coils from the rear bank to the front bank to see if the code follows the coil
Use a scan tool to monitor ionization voltage data on the rear bank while cranking and running
Check for technical service bulletins (TSBs) or PCM software updates specific to this code
If all external components test good, diagnose the PCM for internal circuit faults

Don't overlook the simple ignition components

A loose or corroded ground connection at the rear bank ignition coil can mimic a failed coil and set P1317 without any coil fault.
Aftermarket spark plugs with incorrect heat ranges or resistor values often cause this code on Honda engines even though they appear to work fine.
The spark plug voltage detection circuit is sensitive to electromagnetic interference, so routing of aftermarket wiring or audio cables near the coil harness can trigger false codes.
P1317 can be stored intermittently and may not illuminate the check engine light until the fault occurs multiple times, so a single occurrence should not prompt immediate parts replacement.
On some Honda models, a failing ignition switch or main relay can cause voltage fluctuations that the PCM interprets as a detection circuit fault.

Can I keep driving with P1317?

You can generally continue driving with P1317 if the engine runs smoothly and the check engine light is steady, but avoid heavy acceleration or towing until the fault is repaired. If the light flashes or you notice a pronounced misfire, stop driving to prevent catalytic converter damage.

Tools that help

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Guidance is general and written for Honda vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.