P04AD — EVAP System Purge Control Valve B Circuit High

What Does P04AD Mean?

P04AD is a diagnostic trouble code indicating: EVAP System Purge Control Valve B Circuit High. This code relates to the emission controls system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P04AD

⚠️ Check Engine Light (MIL) illuminated
⚠️ EVAP System Purge Control Valve B reading stuck at maximum value
⚠️ Related system operating erratically or in default mode
⚠️ Failed emissions test

Common Causes

🔍 Short to voltage in EVAP System Purge Control Valve B wiring harness
🔍 Corroded or water-damaged EVAP System Purge Control Valve B connector
🔍 Faulty EVAP System Purge Control Valve B outputting maximum voltage
🔍 Damaged wiring rubbing against metal components
🔍 ECM/PCM internal fault (rare)

Frequently Asked Questions

What does P04AD mean?

P04AD indicates: EVAP System Purge Control Valve B Circuit High. The vehicle's computer has detected that the EVAP System Purge Control Valve B is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P04AD?

Yes, P04AD is generally safe to drive with in the short term. However, it should still be addressed to pass emissions testing and prevent potential secondary issues.

How much does it cost to fix P04AD?

Repair costs for P04AD typically range from $20 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

🔧 Inspect and repair EVAP System Purge Control Valve B wiring for short to voltage
🔧 Clean or replace corroded EVAP System Purge Control Valve B connector
🔧 Replace faulty EVAP System Purge Control Valve B

1
Find your vehicle above
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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.

P04AD: EVAP System Purge Control Valve B Circuit High