P0591: Cruise Control Multi-Function Input B Circuit Range/Performance

Severity

Medium

System

Vehicle Speed and Idle Control

Last reviewed: Jan 1, 0001 Last updated: Jan 1, 0001

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What Does P0591 Mean?

P0591 is a diagnostic trouble code indicating: Cruise Control Multi-Function Input B Circuit Range/Performance. This code relates to the vehicle speed and idle control system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P0591

⚠️ Check Engine Light (MIL) illuminated
⚠️ Cruise Control Multi-Function Input B not operating within expected parameters
⚠️ Reduced efficiency or performance of related system
⚠️ Erratic idle speed

Common Causes

🔍 Cruise Control Multi-Function Input B degraded or contaminated
🔍 Mechanical wear or binding in Cruise Control Multi-Function Input B
🔍 Incorrect Cruise Control Multi-Function Input B installed (wrong part number)
🔍 Related system mechanical issue affecting Cruise Control Multi-Function Input B readings

Frequently Asked Questions

What does P0591 mean?

P0591 indicates: Cruise Control Multi-Function Input B Circuit Range/Performance. The vehicle's computer has detected that the Cruise Control Multi-Function Input B is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P0591?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P0591 for extended periods may cause additional problems.

How much does it cost to fix P0591?

Repair costs for P0591 typically range from $50 to $250, 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

🔧 Inspect and clean Cruise Control Multi-Function Input B
🔧 Replace degraded Cruise Control Multi-Function Input B
🔧 Check for related mechanical issues affecting readings

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.

Related Codes

P0500 Vehicle Speed Sensor A Circuit P0501 Vehicle Speed Sensor A Circuit Range/Performance P0502 Vehicle Speed Sensor A Circuit Low P0503 Vehicle Speed Sensor Circuit Intermittent/High P0504 Brake Switch A/B Correlation P0505 Idle Control System P0506 Idle Control System RPM - Lower Than Expected P0507 Idle Control System RPM - Higher Than Expected P0508 Idle Air Control Circuit Low P0509 Idle Air Control Circuit High