P1320 on Infiniti: How to Diagnose & Fix
Ignition Signal Primary Circuit Malfunction
1 Infiniti model · 1 documented issue · 1 critical
P1320 on Infiniti by model: symptoms, diagnosis and fix
Nissan issued a large 2026 recall covering VC-Turbo four-cylinder vehicles including the Infiniti QX55, QX50 and Altima. Under certain operating conditions the engine can experience high oil temperatures that degrade lubrication of the crankshaft main bearing and the A-, C- and L-link bearings of the variable-compression mechanism. In the worst case a bearing seizes or a failed bearing breaches the engine block, causing catastrophic engine failure. This is a distinct defect from the previously documented oil-consumption issue. Nissan also announced a VC-Turbo warranty extension. Symptoms often precede failure and out-of-warranty engine replacements have run five figures.
Common Symptoms
- Engine knocking or ticking noise
- Metal shavings/debris in engine oil
- Diesel-like pinging at idle
- Sudden loss of power / stalling
- Illuminated check-engine or malfunction light
- Engine seizure
How to Fix
Have the VIN checked for the recall. The remedy reprograms the ECM, scans for diagnostic codes, and inspects the oil pan for metal debris; if metal is found the engine is replaced free of charge. Owners should keep to strict oil-change intervals, use the correct 0W-20 spec oil, and stop driving immediately if knocking, ticking or metal in the oil is noticed. Because a warranty extension applies, keep all service records to protect coverage.
Sources for this issue (3)
P1320 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P1320 mean on a Infiniti?
P1320 stands for "Ignition Signal Primary Circuit Malfunction." Manufacturer-specific powertrain code used by Nissan and Infiniti. The ECM monitors the primary (low-voltage) side of the ignition coil circuits that trigger spark, and sets this code when the ignition primary signal is not returned to the ECM during cranking or running. On many Nissan engines the power transistor that switches the coil is built into the coil-on-plug assembly, so a failed coil often sets this code. Expect misfires, rough idle, hesitation, and in bad cases a flashing check engine light - a flashing light means stop driving, as raw fuel can destroy the catalytic converter. On Infiniti it is documented across 1 model: QX55.
What are the most common causes of P1320?
The most common causes of P1320 are: Failed ignition coil / integrated power transistor (a very common Nissan failure, often one coil at a time), Worn or fouled spark plugs overstressing the coils, Open, shorted, or chafed wiring in the ignition primary circuit, Poor connection or corrosion at an ignition coil connector, Crankshaft or camshaft position sensor fault disrupting the ignition trigger signal, ECM fault (rare - rule out coils and wiring first). The specific cause varies by vehicle.
How much does it cost to fix P1320 on a Infiniti?
Repair costs vary widely with the root cause and Infiniti model; each issue on this page carries its own estimate where one is published.
Looking for P1320 on a different make?
View P1320 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.