P1320: How to Diagnose & Fix — Ignition Signal Primary Circuit Malfunction
2 vehicles · 2 makes · $30-$14,000 repair
How to diagnose and fix P1320: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Infiniti QX55 · 2022–2024
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)
Nissan 240SX · 1991–1998
The KA24DE uses a camshaft-driven distributor that houses the optical Cam Angle Sensor (CAS) and the integral ignition module. Two age-related problems are common. First, the cap-to-distributor O-ring dries out, cracks, and lets oil weep out from under the cap; separately, a clogged PCV valve raises crankcase pressure and pushes oil up into the distributor internally, where it fouls the optical sensor disc and eventually kills the ignition module. Second, the optical CAS itself degrades. Symptoms range from rough running and stalling to no-start, frequently logging Nissan self-diagnostic Code 11 (crank/cam position signal) and Code 21 (ignition signal). Worn cap and rotor contacts add misfire and hard-start complaints.
Common Symptoms
- Oil weeping from under the distributor cap
- Rough idle, random stalling, hard starting
- No-start when hot / heat-related dying
- Misfire from worn cap and rotor
- Self-diagnostic Code 11 and/or Code 21 stored
How to Fix
For weeping oil, replace the distributor cap O-ring and fix the root cause by replacing the PCV valve and clearing crankcase-pressure issues; clean the sensor area. Replace worn cap and rotor and inspect plug wires. If the optical CAS/ignition module is failing (erratic signal, Codes 11/21, heat-related stalling), replace the distributor assembly (reman or OEM) and set base timing. Confirm good grounds before condemning the unit.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- AIP Electronics T2T58071 complete electronic distributor
1994 240SX KA24DE from 02/1994 and 1995-1998 S14 only; not the earlier S13 distributor or connector. Match OE 22100-70F10/T2T58071 before ordering.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
Nissan 240SX · 1991–1998
The KA24DE's distributor houses the optical crank angle sensor (CAS). The internal optical disc and bearings wear with age, causing intermittent or no-start conditions, often throwing ECU codes 11 (crank angle sensor) and 21 (ignition signal). The distributor O-ring also leaks oil into the unit, accelerating failure. Power transistor failure within the distributor circuit can prematurely kill ignition coils.
Common Symptoms
- Intermittent stalling, especially when warm
- No-start with no spark and no injector pulse
- Check engine light with codes 11 and/or 21
- Hard starting
- Oil weeping from distributor base
How to Fix
Replace distributor with OEM Nissan unit (aftermarket units have high failure rates). Replace the distributor base O-ring during install to prevent oil intrusion. Inspect and replace ignition coil and power transistor if showing wear. Verify cam timing before condemning distributor.
Sources for this issue (3)
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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?
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.
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?
Repair costs for P1320 range from $30 to $14,000, depending on the vehicle and root cause.
Which vehicles are affected by P1320?
Au7o has documented P1320 across 2 vehicle models from 2 manufacturers: Infiniti, Nissan.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.