Variable Valve Timing Solenoid B Open Circuit (Ford)
What does P1252 mean?
The P1252 code means the vehicle's onboard diagnostic system has detected: Variable Valve Timing Solenoid B Open Circuit (Ford). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Rough idle
- Reduced engine power
- Poor fuel economy
- Engine rattling at startup
Probable Causes (Ranked by Likelihood)
- Failed VVT solenoid on exhaust camshaft Very High
- Open wiring in VVT solenoid B circuit High
- Corroded VVT solenoid connector Moderate
- PCM VVT driver circuit failure Moderate
- Damaged wiring near valve cover Low
Step-by-Step Diagnostic Procedure
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Measure VVT solenoid B resistance and compare to spec
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Inspect wiring and connector at exhaust VVT solenoid
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Test for 12V supply at solenoid connector with key on
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Check wiring continuity from solenoid to PCM
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Command solenoid activation with scan tool and verify
Frequently Asked Questions
What is VVT solenoid B?
VVT solenoid B typically controls the exhaust camshaft variable valve timing, adjusting exhaust valve timing for optimal power, economy, and emissions.
Can a bad VVT solenoid damage my engine?
It will not cause immediate damage, but prolonged driving can lead to increased wear and poor oil consumption.
Is a VVT solenoid the same as a cam phaser?
No. The VVT solenoid is the electrically controlled oil valve. The cam phaser is the mechanical device that changes camshaft timing.