What Does P004F Mean?
The PCM has detected intermittent or erratic signals from the turbocharger/supercharger boost control 'B' circuit. The secondary boost control solenoid circuit is making and breaking contact unpredictably or showing erratic signal behavior. The driver may notice fluctuating boost pressure, inconsistent power delivery especially during boost-stage transitions, and an intermittent check engine light.
Common Causes
35%
Loose, corroded, or damaged electrical connector at the boost control solenoid 'B'
30%
Intermittent wiring break in the solenoid 'B' harness from vibration or heat damage
20%
Failing boost control solenoid 'B' with intermittent internal coil contact
15%
Poor PCM connector pin contact or intermittent PCM driver output for the 'B' circuit
Diagnostic Steps
1
Review freeze frame data for operating conditions when the fault occurs — note engine load, RPM, and whether the secondary boost system was transitioning on or off.
2
Perform a wiggle test on the solenoid 'B' connector, wiring, and PCM connector while monitoring voltage on the control circuit — use a graphing multimeter to catch brief dropouts.
3
Inspect the solenoid 'B' connector for corroded, spread, or backed-out terminals. Check for signs of water intrusion or melted connector housing from exhaust heat.
4
Measure solenoid coil resistance while physically manipulating the harness and tapping the solenoid — the reading should remain steady. Any fluctuation confirms an intermittent connection.
5
Trace the harness from the solenoid to the PCM looking for chafing, particularly near heat shields, engine mounts, and exhaust components. Repair any damaged sections with heat-resistant wiring.
6
Check all PCM power and ground circuits for excessive voltage drop, which can cause erratic driver behavior across multiple circuits.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
The PCM has detected intermittent or erratic signals from the turbocharger/supercharger boost control 'B' circuit. The secondary boost control solenoid circuit is making and breaking contact unpredictably or showing erratic signal behavior. The driver may notice fluctuating boost pressure, inconsist...
The most common cause of P004F (Turbocharger/Supercharger Boost Control "B" Circuit Intermittent/Erratic) is: Loose, corroded, or damaged electrical connector at the boost control solenoid 'B'
Typical repair costs for P004F range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Drive with caution at moderate speeds. Intermittent secondary boost control can cause unpredictable power transitions. Avoid high-performance driving, towing, or sustained high-load conditions until the intermittent connection is found and repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P004F to identify the root cause.
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Quick Info
Category
Powertrain
System
Forced Induction / Turbocharger
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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