P077B — Output Shaft Speed Sensor Circuit - Direction Error

What Does P077B Mean?

P077B is a diagnostic trouble code indicating: Output Shaft Speed Sensor Circuit - Direction Error. This code relates to the transmission system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P077B

⚠️ Check Engine Light (MIL) illuminated
⚠️ Erratic Output Shaft Speed Sensor readings
⚠️ Related system operating intermittently
⚠️ Harsh or delayed shifting

Common Causes

🔍 Wiring issue in Output Shaft Speed Sensor circuit (damaged, chafed, or corroded)
🔍 Faulty Output Shaft Speed Sensor connector or terminal
🔍 Failed Output Shaft Speed Sensor
🔍 ECM/PCM connection issue

Frequently Asked Questions

What does P077B mean?

P077B indicates: Output Shaft Speed Sensor Circuit - Direction Error. The vehicle's computer has detected that the Output Shaft Speed Sensor is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P077B?

Only short distances if absolutely necessary. P077B affects a critical system and should be diagnosed within a few days to avoid further damage.

How much does it cost to fix P077B?

Repair costs for P077B typically range from $150 to $500, 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 repair Output Shaft Speed Sensor wiring and connectors
🔧 Replace faulty Output Shaft Speed Sensor

1
Find your vehicle above
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2
Check for recalls
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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P077B: Output Shaft Speed Sensor Circuit - Direction Error