P1389 VVT Solenoid 'A' Circuit Malfunction
The P1389 code indicates that the Powertrain Control Module (PCM) has detected an electrical fault in the control circuit of the Variable Valve Timing (VVT) solenoid 'A', typically for the intake camshaft on bank 1. This occurs when the voltage in the command circuit does not match the PCM's commanded state, such as an open circuit, short to ground, or short to battery voltage, preventing proper camshaft phasing adjustment.
01. Most Common Causes
- Faulty VVT solenoid 'A' (open or shorted coil)
- Damaged wiring in the solenoid control circuit (short to ground, short to power, or open circuit)
- Corroded, loose, or pushed-back terminals in the VVT solenoid connector
- Internal PCM driver failure for the solenoid circuit
- Low engine oil pressure or contaminated/sludged oil restricting actuator movement
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle, reduced engine power, or poor fuel economy
03. Step-by-Step Diagnosis
Scan for codes and verify P1389 is present; check for related codes like P0010-P0013.
Inspect VVT solenoid connector and wiring for damage, corrosion, or loose terminals.
Test VVT solenoid resistance with a multimeter (compare to manufacturer specs).
Check engine oil level, condition, and pressure; perform oil change if contaminated.
If wiring and solenoid are good, test PCM output signal; replace PCM if faulty.
1. Frequently Asked Questions
Is it safe to drive?▼
You can drive short distances, but reduced performance and fuel economy may occur. Prolonged driving could lead to engine damage if oil pressure issues are present.
How much does it cost to fix?▼
Repair costs range from $150 to $600, depending on the cause: solenoid replacement ($100-$250), wiring repair ($100-$300), or PCM replacement ($400-$800).