P1390 — Octane Adjust Shorting Bar Out Or Circuit Open

What Does P1390 Mean?

P1390 is a manufacturer-specific diagnostic trouble code: Octane Adjust Shorting Bar Out Or Circuit Open. This code applies to MAZDA, OTHER, BUICK, CADILLAC, CHEVY vehicles. Unlike generic OBD-II codes, manufacturer-specific codes are defined by the vehicle maker and may only apply to certain makes and models.

Symptoms of P1390

⚠️ Check Engine Light (MIL) illuminated
⚠️ No signal from Octane Adjust Shorting Bar Out Or
⚠️ Related system defaulting to backup values
⚠️ Reduced engine performance

Common Causes

🔍 Broken wire in Octane Adjust Shorting Bar Out Or circuit
🔍 Disconnected Octane Adjust Shorting Bar Out Or electrical connector
🔍 Octane Adjust Shorting Bar Out Or internal open circuit failure
🔍 Corroded terminal pins preventing electrical contact

Frequently Asked Questions

What does P1390 mean?

P1390 indicates: Octane Adjust Shorting Bar Out Or Circuit Open. The vehicle's computer has detected that the Octane Adjust Shorting Bar Out Or is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1390?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1390 for extended periods may cause additional problems.

How much does it cost to fix P1390?

Repair costs for P1390 typically range from $30 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Locate and repair broken wire in Octane Adjust Shorting Bar Out Or circuit
🔧 Replace damaged Octane Adjust Shorting Bar Out Or connector
🔧 Replace Octane Adjust Shorting Bar Out Or if internally open

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P1390: Octane Adjust Shorting Bar Out Or Circuit Open